List of Latin Phrases (A)

Form, usage and conventions

Latin phrases in English often appear unchanged or slightly anglicized. Translations may be literal (word-for-word) or idiomatic (conveying the established sense). Capitalization varies by tradition; many legal uses preserve the original lower-case. Some Latin locutions echo earlier Greek formulations—a reflection of how classical Greek literature influenced later Roman thought and rhetoric before and during the era of ancient Rome.

Representative phrases (A)

• a fortiori — "with stronger reason"; used when a conclusion is even more evident than another.
• a contrario — "from the opposite"; reasoning by contrast.
• ab initio — "from the beginning"; used in law and science to denote origin.
• ab ovo — "from the egg"; figuratively, from the very start.
• ad absurdum — "to absurdity"; often part of reductio ad absurdum (reduction to absurdity).
• ad acta — "to the files"; meaning a matter is filed away or closed.
• ad astra — "to the stars"; found in mottos and poetry (e.g., aspirational slogans).
• ad hoc — "for this"; temporary, improvised, or for a specific purpose.
• ad hominem — "to the person"; an argument attacking the opponent rather than the issue.
• ad idem — "to the same"; used when parties agree.
• ad infinitum — "to infinity"; endlessly or without limit.
• ad interim — "in the meantime"; temporarily in office or position.
• ad libitum (ad lib) — "at pleasure"; freely, or by improvisation (music, speech).
• ad nauseam — "to the point of nausea"; repeated so much it becomes tiresome.
• alea iacta est — "the die is cast"; attributed to Julius Caesar on passing a point of no return.
• alibi — "elsewhere"; commonly used in law to indicate being elsewhere when an act occurred.
• alma mater — "nourishing mother"; used for a school or university one attended.
• anno Domini (A.D.) — "in the year of the Lord"; used in dating years in the Christian era.
• a priori — "from the former"; knowledge or reasoning independent of particular experience.
• a posteriori — "from the latter"; knowledge or reasoning based on experience.
• argumentum ad populum — "appeal to the people"; a fallacy that appeals to popular opinion.

History and importance

Many of these phrases entered English during the Middle Ages and Renaissance, when Latin was the language of scholarship, law, and the Church. Over centuries they became fixed technical terms in law, theology, philosophy, and science. Today they serve both precise technical roles (for example in legal citations) and general rhetorical ones (mottos, quotations).

Distinctions and notes

When using Latin phrases, distinguish literal translation from accepted idiomatic sense; some phrases have technical legal meanings that differ from casual usage. For fuller alphabetical coverage beyond A, consult the main list. For background on classical influences see discussions of Greek literature and Roman practice in ancient Rome.