Latin and Greek phrases are littered through the English Language; some are used by the commonly everyday , others are specialized terms used in law, medicine, science or academia. Here are some of them with their respective meanings:
ab initio – from the beginning – in law, the beginning of an investigation. In literature, the beginning of a story.
ad hoc – to this – Generally means “for this”, in the sense of improvised or intended only for a specific, immediate purpose; used in the sense of a “temporary measure or arrangement”.
ad hominen – to the man – or “targeting the man”. An ad hominen attack refers to the attack on the person making the argument instead of attacking the argument.
ad infinitum – to infinity – Enduring forever or repeating forever. Enduring forever. Used to designate a property which repeats in all cases in mathematical proof. Also used in philosophical contexts to mean “repeating in all cases”.
ad interim – for the meantime.
ad nauseaum – to sea sickness – or “to the point of disgust “. used to refer to something that is repeated endlessly until the persons listening are “sick of it”
ad valorem – according to the value – Used in commerce to refer to ad valorem taxes, i. e., taxes based on the assessed value of real estate or personal property.
addendum – thing to be added – An item to be added, especially as a supplement to a book. The plural is addenda.
affidavit – he asserted – A legal term from “fides” (“faith”), originating at least from Medieval Latin to denote a statement under oath.
alias – at another time, otherwise – An assumed name or pseudonym; similar to alter ego, but more specifically referring to a name, not to a “second self”.
alibi – elsewhere – A legal defense where a defendant attempts to show that he was elsewhere at the time a crime was committed. For example: His alibi is sound; he gave evidence that he was in another city on the night of the murder.
alma mater – nourishing mother – A term used for the university one attends or has attended. Another university term, matriculation, is also derived from mater. The term suggests that the students are “fed” knowledge and taken care of by the university. The term is also used for a university’s traditional school anthem.
alter ego – another I – Another self, a second persona or alias. Can be used to describe different facets or identities of a single character, or different characters who seem representations of the same personality. Often used of a fictional character’s secret identity.
alumnus or alumna – pupil – Graduate or former student of a school, college, or university. Plural of alumnus is alumni (male). Plural of alumna is alumnae (female).
amicus curiae – friend of the court – An adviser, or a person who can obtain or grant access to the favour of a powerful group, e. g., the a Roman Curia. In current United States legal usage, an amicus curiae is a third party allowed to submit a legal opinion in the form of an amicus brief to the court.