| ο | = | the |
| ο Άγιος Ιωάννης ο Πρόδρομος | = | John the Baptist |
| ο δείπνος | = | supper |
| ο δικός μας | = | our |
| ο δικός τους | = | their |
| ο δρόμος στενεύει | = | road narrows |
| ο εαυτός μου | = | myself |
| ο εαυτός σας | = | yourself, yourselves |
| ο εαυτός σου | = | yourself |
| ο εαυτός του | = | himself |
| ο ένας τον άλλο | = | each other |
| ο εξαποδώ | = | devil |
| ο εξαποδώ | = | Satan |
| ο έξω ορθός μυς του οφθαλμού | = | lateral rectus, rectus lateralis, rectus externus |
| ο έσω ορθός του οφθαλμού | = | medial rectus, rectus medialis, rectus internus |
| ο ηθοποιός | = | actor |
| ο θάνατος | = | the grim reaper |
| ο Θεός να φυλάξει | = | Heaven forbid |
| ο Θεός ξέρει τι είναι αυτό | = | whatever that may be |
| ο καθένας | = | each |
| ο καθρέφτης της ψυχής | = | the window of the soul |
| ο κακός | = | villain |
| ο καλός ο κακός και ο άσχημος | = | the good the bad and the ugly |
| ο καλύτερος | = | best, second to none |
| ο κανόνας ισχύει για σένα | = | the rule applies to you |
| ο κατηγορούμενος | = | the accused |
| ο κήπος της Εδέμ | = | Garden of Eden |
| ο κόσμος είναι δικός μου | = | the world is my oyster |
| ο κόσμος έχει ξεχαρβαλωθεί | = | the times are out of joint |
| ο κύβος ερρίφθη | = | the die is cast |
| ο κυνηγός κυνηγημένος | = | the biter bitten |
| ο λόγος διήγειρε το λαό | = | stirred up |
| ο λουφές της εξουσίας | = | spoils of office |
| ο μαθητευμένος μάγος | = | the sorcerer's apprentice |
| ο μεγαλύτερος εχθρός | = | archenemy |
| ο μέσος άνθρωπος | = | man in the street |
| ο μετρητής τρέχει | = | the meter is running |
| ό μη γένοιτο | = | God forbid |
| ο μήνας έχει εννέα | = | couldn΄t care less |
| ο νόμος κατά γράμματος | = | the letter of the law |
| ο οποίος | = | who |
| ο παθών | = | sufferer |
| ο περισσότερος | = | most |
| ο πιο απότομος | = | the most sudden |
| ο πιο αυστηρός | = | the strictest |
| ο πιο γλυκός | = | the sweetest |
| ο πιο δυνατός | = | the strongest |
| ο πιο πολύς | = | most |
| ο πλησιέστερος συγγενής | = | next of kin |
| ο προσήκων σεβασμός | = | due respect |
| ο πρώτος .... ο δεύτερος | = | the former .... the latter |
| ο ραπτικός μυς | = | sartarius |
| ο σερβιτόρος | = | waiter |
| ο σκοπός αγιάζει τα μέσα | = | end justifies the means |
| ο σύζυγος | = | husband |
| ο τελευταία αναφερόμενος | = | latter |
| ο χειρίτερος | = | worst |
| ο χειρότερος | = | worst |
| όαση | = | oasis |
| οβάλ | = | oval |
| οβελίσκος | = | obelisk |
| οβίδα | = | shell |
| όγδοο νότας | = | quaver |
| όγδοος | = | eighth |
| ογκόλιθος | = | block of stone |
| όγκος | = | growth, tumour, volume |
| ογκώδης | = | massive |
| οδήγησα | = | led |
| οδήγησε | = | he led, he drove, she led, she drove |
| οδήγησες | = | you led, you drove |
| οδήγηση | = | driving, motoring |
| οδηγία | = | directive, guideline |
| οδηγίες | = | directions, instructions |
| οδηγός | = | driver, guide, guide book, guidebook, guideline |
| οδηγός συσκευής | = | device driver |
| οδηγός τραίνου | = | engine driver |
| οδηγώ | = | drive, steer a boat / a car, steer [boat, car], l |
| οδηγώ αμάξι | = | steer |
| οδηγώ αυτοκίνητο | = | drive a car |
| οδηγώ σε | = | lead to |
| οδηγώ σε αδιέξοδο | = | lead to a dead end |
| οδηώ | = | steer the car |
| οδικά έργα | = | men at work, roadworks |
| οδική πινακίδα | = | road sign |
| οδικός χάρτης | = | road map |
| οδοιπορία | = | trek |
| οδοντίατρος | = | dentist |
| οδοντικός | = | dental |
| οδοντόβουρτσα | = | toothbrush |
| οδοντογλυφίδα | = | toothpick |
| οδοντόπαστα | = | toothpaste |
| οδοντοστοιχίες | = | dentures |
| οδοντοφυΐα | = | teething |
| οδοντωτός | = | toothed, serrated |
| οδοντωτός τροχός αναστολής | = | ratchet |
| οδός | = | street |
| οδός προσπέλασης | = | access road |
| οδοσήμανση | = | road markings |
| οδόφραγμα | = | barricade |
| οδοφράγματα | = | barracades |
| οδύνη | = | grief |
| οδυνηρά | = | painfully |
| οδυνηρός | = | painful |
| οδυρμός | = | lament |
| όζον | = | ozone |
| όζος | = | node |
| όθεν | = | hence |
| οθόνη | = | display |
| οθόνη | = | monitor, display |
| οθόνη αφής | = | touch screen |
| οθόνη βίντεο | = | video screen |
| οθώνη | = | screen |
| οι | = | the |
| οι αγαπημένοι | = | loved ones |
| οι άλλες | = | others |
| οι άλλοι | = | others |
| οι Άλπες | = | the Alps |
| οι εαυτοί μας | = | ourselves |
| οι εαυτοί μας / εμείς οι ίδιοι | = | ourselves |
| οι εαυτοί σας | = | yourselves |
| οι εαυτοί σας / εσείς οι ίδιοι | = | yourself, yourselves |
| οι εαυτοί τους | = | themselves |
| οι ένορκοι | = | jury |
| οι ιθύνοντες | = | those in power |
| οι καλές ημέρες | = | good times |
| οι Κάτω Χώρες | = | The Netherlands |
| οι παλιές καλές μέρες | = | good old days |
| οι πιο πολλοί από | = | the majority of |
| οι συμμετάσχεντες | = | participants |
| οι Συντηρητικοί | = | the Conservatives |
| οι υψηλά ιστάμενοι | = | high and mighty |
| οι φήμες λένε | = | rumour has it |
| οικειοποιούμαι | = | appropriate |
| οικείος | = | intimate |
| οικειότητα | = | familiarity |
| οίκημα | = | premise, premises |
| οικιακά | = | home economics |
| οικιακές συσκευές | = | conveniences |
| οικιακοί βοηθοί | = | domestic staff |
| οικιακός | = | domestic, household |
| οικισμός | = | housing estate, settlement |
| οικιστής | = | settler |
| οικιστικός | = | residential |
| οικογένεια | = | household, family, pedigree |
| οικογενειακός γιατρός | = | family doctor |
| οικογένια | = | family |
| οικοδέσποινα | = | hostess |
| οικοδεσπότης | = | host |
| οικοδόμος | = | builder |
| οικοδομώ | = | construct |
| οικοκυρά | = | housewife |
| οικολογία | = | ecology |
| οικολογικά | = | ecologically |
| οικολογικός | = | ecological |
| οικολόγος | = | ecologist |
| οικονομία | = | saving |
| οικονομικά | = | econimcally |
| οικονομικά φειδωλά | = | sparingly |
| οικονομική | = | economics |
| οικονομική άνθηση | = | boom |
| οικονομική βοήθεια | = | financial aid |
| οικονομική περιφέρεια | = | economic area |
| οικονομικός | = | economic, financial |
| οικονομικός σύμβουλος | = | financial advisor |
| οικονομολογία | = | economics |
| οικονομολόγος | = | economist |
| οικονόμος | = | steward, seneschal |
| οικόπεδο | = | building site |
| οίκος | = | house |
| οίκος ευγηρίας | = | rest-home |
| οίκος μόδας | = | fashion house |
| οικόσημο | = | coat of arms, crest |
| οικοσημολογία | = | heraldry |
| οικοσύστημα | = | ecosystem |
| οικοτροφείο | = | boarding school |
| οικότροφος μαθητής | = | boarder |
| οίκτος | = | pity, compassion |
| οικτρός | = | pitiful |
| οινόπνευμα | = | alcohol |
| οινοπνευματώδες ποτό | = | mescal |
| οινοπότης | = | wine drinker |
| οίνος | = | wine |
| οινωπνευματώδης | = | alcoholic |
| οιονεί | = | quasi |
| οισοφάγος | = | esophagus |
| οισόφαγος | = | gullet |
| οισοφάφος | = | esophagus |
| οίστρος | = | gadfly |
| οιωνοί | = | auspices |
| οκνηρά | = | lazily |
| οκνηρία | = | laziness, boredom |
| οκνός | = | nonchalant |
| Οκτώβριος | = | October |
| όλα | = | everything, all |
| όλα δέιχνουν ότι | = | everything indicates that |
| ολέθριος | = | pernicious, devastating, baleful |
| όλεθρος | = | disaster, devastation |
| όλες | = | all |
| όλη την ώρα | = | all the time |
| ολιγαρχία | = | oligarchy |
| ολιγολογία | = | reticence |
| ολική | = | calibre |
| ολική έκλειψη | = | total eclipse |
| ολικός | = | total, full |
| ολίσθημα | = | slip, lapsus |
| ολισθηρός | = | slippery |
| Ολλανδέζικος | = | Dutch |
| Ολλανδία | = | Holland |
| Ολλανδοί | = | Dutch |
| όλμος | = | shell |
| όλο καημό | = | wistful |
| όλο ύφος και καμώματα | = | all airs and graces |
| ολόγυμνος | = | stripped naked |
| ολοένα και περισότερα | = | more and more |
| όλοι | = | everyone, everybody, all, all and sundry |
| όλοι στο πλοίο | = | all aboard |
| όλοι στο πλοίο / τρένο | = | all aboard |
| ολόιδιος | = | identical |
| ολοκαύτωμα | = | holocaust |
| ολόκληρος | = | entire, whole, complete, all-round |
| ολοκληρωμένη προσωπικότητα | = | integrated personality |
| ολοκληρωμένο κύκλωμα | = | integrated circuit |
| ολοκληρώνω | = | complete, accomplish, top off |
| ολοκλήρωση | = | completion |
| ολοκληρωτικός | = | totalitarian |
| ολοκληρωτικός λογισμός | = | integral calculus |
| ολοκληρωτικός λογισμός | = | integral calculus |
| ολοκληρωτισμός | = | totalitarianism |
| ολομέλεια | = | plenary session, plenum |
| όλος | = | all |
| ολόσωμα | = | overalls |
| ολόσωμη εφαρμοστή φόρμα | = | catsuit |
| ολοφάνερος | = | glaring |
| Ολυμπιακός | = | Olympic |
| ομάδα | = | team, group |
| ομάδα αποστατών | = | splinter group |
| ομαδική διαταγή | = | batch command |
| ομαδικό αρχείο | = | batch file |
| ομαλά | = | smoothly |
| ομαλός | = | regular |
| ομελέτα | = | omelette |
| ομήγυρη | = | assembly, company |
| όμηρος | = | hostage |
| ομιλητής | = | speaker |
| ομιλητικός | = | talkative |
| ομιλία | = | talk, parole, homily |
| όμιλος | = | group |
| ομίχλη | = | fog, mist |
| ομίχλη κατά τόπους | = | patches of fog |
| ομιχλώδης | = | foggy, misty |
| ομοειδής | = | associated |
| ομοιογενής | = | homogeneous |
| ομοιομορφία | = | uniformity |
| ομοιόμορφος | = | uniform |
| ομοιοπαθητικός | = | homeopath |
| όμοιος | = | similar to, alike, peer |
| όμοιος και απαράλλακτος | = | indistinguishable |
| ομοιότητα | = | similarity |
| ομοιπαθητικό φάρμακο | = | alternative medicine |
| ομόλογα | = | bonds |
| ομολογία | = | admission, avowal |
| ομόλογο | = | bond |
| ομόλογος | = | counterpart |
| ομολογουμένως | = | admittedly |
| ομολογώ | = | confess, avow |
| ομολογώ σε | = | confess to |
| ομολογώ το φταίξιμο | = | own up |
| ομόνοια | = | togetherness, concord |
| ομορφιά | = | beauty |
| όμορφος | = | beautiful, good-looking |
| όμορφος (άνδρας) | = | handsome |
| ομοσπονδία | = | federation |
| ομοσπονδιακός | = | federal |
| ομοσπωνδiα | = | association |
| ομότιμο πρωτόκολλο | = | peer protocol |
| ομότιμος | = | peer |
| ομοφονία | = | concord |
| ομοφυλοφιλία | = | homosexuality |
| ομοφυλόφιλος | = | gay |
| ομόφωνα | = | unanimously |
| ομοφωνία | = | consensus |
| ομόφωνος | = | unanimous |
| όμποε | = | oboe |
| ομπρέλα | = | umbrella |
| όμφαες εισίν | = | it's sour grapes |
| όμφακες εισί | = | sour grapes |
| όμφακες εισίν | = | it's sour grapes |
| ομφάλιος λώρος | = | umbilical cord |
| ομώνυμη λέξη | = | homonym |
| όμως | = | however, but, nonetheless |
| όν | = | being |
| ΟΝΕ | = | EMU |
| ονειδίζω | = | vituperate |
| όνειδος | = | ignominy |
| ονειρεύομαι | = | dream |
| όνειρο | = | dream |
| ονειροπόληση | = | daydream |
| ονειροπολώ | = | day dream, daydream |
| όνομα | = | name |
| ονομάζεται | = | is called |
| ονομάζω | = | name |
| ονομασία | = | name |
| ονομαστικά | = | by name |
| ονομαστική εορτή | = | name day, nameday |
| ονομαστικός | = | nominal |
| ονομαστικός | = | nominative |
| ονομαστός | = | reputable |
| ονοματί | = | called |
| ονοματολογία | = | nomenclature |
| οντότητα | = | entity |
| οντότητα | = | entity |
| οντότητα | = | entity |
| οντότητα | = | entity |
| ονυχοφαγία | = | nailbiting |
| οξαλίδα | = | sorrel |
| οξεία αίσθηση του χιούμορ | = | keen sense of humour |
| οξεία γωνία | = | oblique angle |
| οξείδιο | = | oxide |
| οξείδωση | = | oxidation |
| οξικό άλας | = | acetate |
| οξικός | = | acetic |
| όξινη βροχή | = | acid rain |
| οξινίζω | = | acidify |
| όξινος | = | acidic |
| οξύ | = | acid |
| οξυά | = | beech |
| οξυγόνο | = | oxygen |
| οξυγονοκολλώ | = | weld |
| οξυγόνωση | = | oxygenation |
| οξυδέρκεια | = | acuity, sharpness |
| οξυδερκής | = | keen, sharp, acute, discriminating, perceptive |
| οξυθυμία | = | irascibility |
| οξύθυμος | = | irritable, petulant, quick-tempered, irascible |
| οξύνοια | = | acumen |
| οξύνους | = | sharp-witted |
| οξύνω | = | acidify, exacerbate |
| οξύρρυγχος | = | sturgeon |
| οξύς | = | acid, acute |
| οξύτερος | = | keener, more pungent |
| οξύτητα | = | asperity, acerbity |
| οπαδοί | = | following |
| οπαδός | = | fan, adherent, aficionado, supporter, devotee |
| όπερ έδει δείξαι | = | quod erat demonstrandum |
| όπερα | = | opera |
| οπή | = | aperture, borehole |
| όπισθεν | = | reverse |
| οπίσθιος θάλαμος | = | posterior chamber |
| οπισθογράφηση | = | endorsement |
| οπισθογραφώ | = | endorse |
| οπισθοδρομώ | = | retreat |
| όπλα | = | arms |
| οπλή | = | hoof (hooves), hoof |
| οπλισμένος | = | armed |
| οπλισμένος σαν αστακός | = | armed to the teeth |
| οπλισμός | = | weaponry |
| όπλο | = | gun, arm |
| οπλοστασίο | = | arsenal |
| οποιοδήποτε | = | whichever |
| οποιοσδήποτε | = | whoever |
| οποτεδήποτε | = | whenever |
| όπου | = | where |
| οπουδήποτε | = | wherever, anywhere |
| οπτασία | = | apparition |
| οπτικά | = | visually |
| οπτικά βοηθήματα | = | visual aids |
| οπτική γωνία | = | visual angle |
| οπτική τέχνη | = | visual art |
| οπτικό πεδίο | = | field of vision |
| οπτικοακουστικός | = | audiovisual |
| οπτικός | = | visual, optician |
| όπως | = | like, as, such as |
| όπως έχουν τα πράγματα | = | as things stand now |
| όπως το έλεγε | = | as he put it |
| όπως του επισημάνθηκε | = | as it was pointed out to him |
| όραμα | = | vision |
| οραματίζομαι | = | visualise |
| οραματιστής | = | visionary |
| όραση | = | eyesight, sight, vision |
| ορατός | = | visible to, visible |
| ορατός από | = | in sight of |
| ορατότητα | = | visibility |
| οργανική ύλη | = | organic matter |
| οργανικός | = | organic |
| οργανίστας | = | organist |
| όργανο | = | organ, instrument, implement |
| οργανωμένες διακοπές | = | package holiday |
| οργανώνω | = | organise, mastermind |
| οργανώνω αποδοτικά | = | to streamline |
| οργανώνω εκλογές | = | hold elections |
| οργανώνω πάρτι | = | throw a party |
| οργάνωση | = | organisation |
| οργανωτής | = | organiser |
| οργασμός | = | orgasm |
| οργή | = | anger, fury, rage, temper, outrage |
| οργιά | = | fathom |
| οργιαστκός | = | rampant |
| οργίλα | = | wrathfully |
| οργίλος | = | wrathful |
| όργιο | = | riot, orgy |
| οργισμένος | = | angry, furious, irate, in high dudgeon, resentful |
| οργισμένος για | = | furious about |
| οργισμένος με | = | furious with |
| οργιστικά | = | rampantly |
| οργώνω | = | plough |
| οργωτής | = | ploughman |
| ορδή | = | horde |
| ορειβασία | = | climbing, mountaineering |
| ορειβάτης | = | mountaineer, climber |
| ορειβατικό μπαστούνι | = | alpenstock |
| ορεινή λίμνη | = | tarn |
| ορεινή περιοχή | = | highland |
| ορεινός | = | mountainous |
| ορεκτικά | = | starters |
| ορεκτικό | = | antipasto, starter |
| ορεκτικός | = | appetising |
| όρεξη | = | appetite |
| ορθάνοιχτος | = | wide open |
| όρθιος | = | standing, upright |
| όρθιος μυς | = | rectus |
| ορθογραφία | = | dictation, spelling |
| ορθογραφώ | = | spell, spelled, spelt |
| ορθογώνιο | = | rectangle |
| ορθοδοντικός | = | orthodontist |
| ορθοδοξία | = | orthodoxy |
| ορθόδοξος | = | orthodox |
| ορθοστασία | = | handstand |
| ορθοστάτες | = | legs |
| ορθότητα | = | accuracy, rectitude, advisability |
| ορθώνομαι | = | rise, stand up |
| ορθώνω | = | erect, put up |
| ορθώνω τις τρίχες | = | bristle |
| οριακά | = | marginally |
| οριακή πιθανότητα | = | marginal probability |
| οριακός | = | borderline, marginal |
| ορίζοντας | = | horizon, vista |
| οριζόντιο δοκάρι | = | crossbar |
| οριζόντιος | = | horizontal |
| ορίζω | = | appoint, prescribe |
| ορίζω χρόνο | = | set a time |
| όριο | = | limit, boundary |
| όριο ζωής | = | lifespan |
| όριο θραύσης | = | tensile strength |
| όριο ταχύτητας | = | the speed limit, speed limit |
| οριοθετώ | = | delimit |
| ορισμός | = | assignment, appointment, definition |
| όρισμος | = | determination |
| οριστικά | = | definitely |
| οριστικοποιώ | = | finalise |
| οριστικός | = | definite, cut and dried |
| όρκα | = | killer whale |
| ορκίζομαι | = | swear, swore, sworn, vow |
| ορκισμένος | = | sworn |
| όρκος | = | oath, vow |
| ορκωτός λογιστής | = | chartered accountant |
| ορμέμφυτος | = | impulsive |
| ορμή | = | rush, impulse, impetuosity, impact |
| ορμητικός | = | impetuous, surging |
| ορμίσκος | = | cove, small bay |
| ορμόνη | = | hormone |
| ορμώ | = | rush at, pour, rush, burst into, dash, hurtle |
| ορμώ κάτω | = | plough down |
| ορνιθοειδής | = | avian |
| ορνιθοσκαλίσματα | = | scribble |
| όρνιο | = | griffin vulture |
| οροθεσία | = | demarcation, landmark |
| οροθετώ | = | delimit |
| ορολογία | = | terminology |
| οροπέδιο | = | plateau |
| όρος | = | mountain, term, mount, stipulation |
| οροσειρά | = | mountain chain |
| ορόσημο | = | landmark |
| οροφή | = | roof, sunroof |
| οροφή πλεύσης | = | cruising ceiling |
| οροφηή | = | the roof |
| όροφος | = | storey, floor |
| ορτανσία | = | hydrangea |
| ορτυγομάννα | = | corncrake |
| ορτύκι | = | quail |
| ορυκτέλαιο | = | mineral oil |
| ορυκτερόπους | = | aardvark |
| ορυκτό | = | ore |
| ορυκτολογία | = | mineralogy |
| ορυχείο | = | mine, pit |
| ορφανός | = | orphan |
| ορφανός από μητέρα | = | motherless |
| ορφανός από πατέρα | = | fatherless |
| ορφανοτροφείο | = | orphanage |
| ορχήστρα | = | orchestra |
| ορχηστρικός | = | orchestral |
| όρχις | = | testicle |
| όσιος | = | sacred |
| οσμή | = | odour, scent |
| όσο θυμάμαι | = | within living memory |
| όσο κι'αν | = | however |
| όσο να πείς κρεμμύδι | = | as soon as you could say Jack Robinson |
| όσο πλούσιος κι’αν είναι | = | however rich he is |
| όσον αφορά | = | vis ΰ vis |
| όσπρια | = | pulses, legumes |
| οστάριο | = | ossicle |
| οστεΐνη | = | cement |
| οστεοπόρωση | = | osteoporosis |
| οστούν | = | bone |
| όστρακο | = | shell |
| οστρακοειδή | = | shellfish |
| οστρακοειδής | = | crustacean |
| οσφαίνομαι | = | smell |
| οσφύς | = | loin |
| όσχεο | = | scrotum |
| όταν | = | when |
| όταν πρόκειται για | = | when it comes to |
| όταν σε γνωρίζω καλύτερα | = | on further acquaintance |
| ότι κι'αν λεει | = | whatever he says |
| ότι κι αν κάνω | = | no matter what I do |
| οτιδήποτε | = | whatever |
| οτοστόπ | = | hitchhiking |
| Ουαλλία | = | Wales |
| ουαλλικός | = | welsh |
| ουαλλός | = | Welshman |
| Ουγγαρία | = | Hungary |
| Ούγγρος | = | Hungarian |
| ούγια | = | selvage, webbing, hem |
| ουγκιά | = | ounce |
| ουδέτερος | = | neutral |
| ούζο | = | ouzo |
| ουίσκι | = | scotch |
| ούλα | = | gums |
| ουλή | = | scar |
| ούλο | = | gum |
| ουρά | = | tail |
| ούρα | = | urine |
| ουρά αλεπού | = | bush |
| ουραίο | = | breech |
| ουράνιο τόξο | = | rainbow |
| ουρανίσκος | = | palate |
| ουρανοξύστης | = | skyscraper |
| ουρανός | = | sky, heaven |
| ουρητήριο | = | urinal |
| ουρλιάζω | = | howl |
| ουροποιητικό σύστημα | = | urinary system |
| ουρώ | = | pass water |
| ουσία | = | substance, matter, essence |
| ουσία που επαναφέρει τα μαλλιά | = | hair restorer |
| ουσία που προκαλεί αλλεργία | = | allergen |
| ουσιαστικά | = | essentially, fundamentally, virtually |
| ουσιαστικό | = | substantive, noun |
| ουσιαστικός | = | substantial |
| ουσιώδης | = | fundamental, vital, essential, indispensable |
| ούτε | = | nor, either |
| ούτε .... ούτε | = | neither ..... nor |
| ούτε εγώ | = | neither do I |
| ουφώ | = | suck |
| οφείλω | = | owe, be in debt to |
| όφελος | = | avail, benefit |
| οφθαλμολογία | = | opthalmology |
| οφθαλμολόγος | = | oculist |
| οφθαλμόν αντί οφθαλμού | = | eye for an eye, tit for tat |
| οφθαλμοπορνεία | = | lascivious look |
| οφθαλμός | = | eye |
| όφις | = | snake |
| όφσαϊντ | = | offside |
| όφσετ | = | offset |
| οχετός | = | sewer, gutter, drain, conduit |
| όχημα | = | vehicle |
| όχημα εκτόξευσης | = | launch vehicle |
| όχθη | = | bank, riverside |
| οχθοτούρλι | = | black tailed godwit |
| όχι | = | no |
| οχι αρμονικός | = | anharmonic |
| όχι ευκαταφρόνητος | = | considerable |
| όχι καλά | = | unwell |
| όχι μόνο ... αλλά | = | not merely ... but |
| όχι πια | = | any longer |
| όχι πιά | = | no longer |
| όχι πιά της μόδας | = | out of fashion |
| όχι πλέον | = | any longer |
| όχι σαν | = | unlike |
| όχι της μόδας | = | old fashioned |
| όχι τόσο καλός όσο | = | not so good as |
| όχι φοβισμένος | = | unintimidated |
| οχιά | = | viper, adder |
| όχιπλέον | = | any longer |
| όχληση | = | vexation |
| όχλος | = | mob |
| οχυρό | = | fortress, stronghold |
| οχυρώνω | = | embattle |
| οχυρώνω. ενισχύω | = | fortify |
| οχύρωση | = | fortification |
| όψη | = | aspect, countenance |
| οψιανός | = | obsidian |
| όψιμος | = | late |