O

O diem praeclarum! - Oh, what a beautiful day!

O praeclarum custodem ovium lupum! - An excellent protector of sheep, the wolf! (Cicero)

O quam cito transit gloria mundi! - O how quickly passes the glory of the world!

O sancta simplicitas! - Oh, holy simplicity! (Jan Hus)

O tempora, O mores! - O the times, O the customs! (Cicero)

O! Plus! Perge! Aio! Hui! Hem! - Oh! More! Go on! Yes! Ooh! Ummm!

Obesa cantavit - The fat lady has sung

Omne ignotum pro magnifico est - We have great notions of everything unknown. (Tacitus)

Omne initium est difficile - Every beginning is difficult

Omne trium perfectum - Everything that comes in threes is perfect

Omnes aequo animo parent ubi digni imperant - All men cheerfully obey where worthy men rule. (Syrus)

Omnes lagani pistrinae gelate male sapiunt - All frozen pizzas taste lousy

Omnes una manet nox - The same night awaits us all. (Horace)

Omnes vulnerant, ultima necat - All (hours) wound, the last kills. (inscription on solar clocks)

Omnia iam fient quae posse negabam - Everything which I used to say could not happen will happen now. (Ovid)

Omnia mea mecum porto - All that is mine, I carry with me. (Cicero)

Omnia mors aequat - Death equals all things

Omnia mutantur, nihil interit - Everything changes, nothing perishes. (Ovid)

Omnia mutantur nos et mutamur in illis - All things change, and we change with them

Omnia vincit amor; et nos cedamus amori - Love conquers all things; let us too surrender to love. (Vergil)

Omnium rerum principia parva sunt - Everything has a small beginning. (Cicero)

Optimus magister, bonus liber - The best teacher is a good book

Ora et labora - Pray and labor. (St. Benedict)

Osculare pultem meam! - Kiss my grits!