| Word | Meaning | Occurrences |
|---|---|---|
| onus | load, burden | 82 |
| onusto | to burden, load | 1 |
| onustus | loaded, burdened | 3 |
| onychinus | onyx | 9 |
| onyx | onyx | 2 |
| ooliab | Ooliab | 4 |
| ooliba | Ooliba | 6 |
| oolibama | Oolibama | 8 |
| oolla | Oolla | 5 |
| oozam | Oozam | 1 |
| opacus | shaded, shady | 1 |
| opera | service, exertion | 13 |
| operarius | laborer, worker | 39 |
| operatio | working, activity | 32 |
| operator | worker | 3 |
| operculum | cover, covering | 1 |
| operimentum | covering, cover | 23 |
| operio | to cover, clothe | 198 |
| operor | to work, do | 316 |
| opertorium | covering, garment | 3 |
| opertus | hidden | 8 |
| ophaz | Ophaz | 1 |
| ophel | Ophel | 4 |
| opher | Opher | 3 |
| ophera | Ophera | 1 |
| ophi | Ophi | 1 |
| ophim | Ophim | 1 |
| ophiomachus | a kind of locust | 1 |
| ophir | Ophir | 9 |
| ophlal | Ophlal | 2 |
| ophni | Ophni | 6 |
| ophra | Ophra | 1 |
| opifex | worker, artisan | 2 |
| opilio | shepherd | 1 |
| opinatus | illustrious, renowned | 1 |
| opinio | opinion, supposition | 6 |
| opitulatio | helping, assisting | 2 |
| opitulor | to bring aid, help | 1 |
| oportet | it is necessary | 227 |
| oppando | to spread out before | 2 |
| oppido | very, exceedingly | 3 |
| oppidum | town | 45 |
| oppilo | to stop up, shut up | 3 |
| oppono | to set before, to pledge | 6 |
| opportune | conveniently, in due season | 4 |
| opportunitas | convenience, opportunity | 8 |
| opportunus | opportune, timely | 21 |
| oppositio | opposition | 2 |
| oppressio | pressing down, suppression | 1 |
| opprimo | to oppress, to violate | 84 |
| opprobrium | disgrace | 98 |
| oppugno | to fight against, attack | 18 |
| ops | means, property | 24 |
| optatus | wished, desired | 3 |
| optimas | of the best, noblest | 34 |
| optio | choice, free choice | 3 |
| opto | to choose, select | 9 |
| opulentus | rich, wealthy | 9 |
| opus | work, need | 954 |
| ora | edge, fringe | 21 |
| oraculum | divine announcement, oracle | 26 |
| oratio | speech, prayer | 212 |
| orator | speaker, orator | 2 |
| oratorium | place of prayer, oratory | 1 |
| orbis | circle, sphere | 90 |
| orbo | to deprive, strip | 3 |
| ordinate | in an orderly manner | 1 |
| ordinatio | decree, edict | 3 |
| ordinator | ordainer, regulator | 1 |
| ordino | to arrange, set in order | 34 |
| ordior | to begin a web, lay the warp | 3 |
| ordo | order, rank | 90 |
| oreb | Oreb | 7 |
| organum | musical instrument | 18 |
| oriens | the rising sun, the east | 106 |
| orientalis | eastern | 83 |
| originalis | primitive, original | 2 |
| origo | beginning, origin | 8 |
| orion | Orion | 2 |
| orior | to rise, come forth | 102 |