Latin terms we use

Ad hoc is a Latin term meaning "for this purpose".
Ad hominem is a Latin term meaning "to the man".
Ad infinitum is the Latin for "to infinity."
Amicus curiae is the Latin for "a friend of the court."
Bona Fide means "in good faith."
Caveat Emptor: "Let the buy beware.":
Circa: Approximately. Used with dates, also abbreviated ca.
Confer: Compare. Usually abbreviated cf., often used in footnotes, indicates to compare the present passage or statement with the one referenced.
Cum laude: "With praise."
De facto means "in fact."
De jure means "based in law."
De novo means "anew."
Erratum/errata: Literally, "error/errors," this term in fact refers to the corrections included in a paper or book after it is published to correct minor errors in the text.
Ergo: Therefore. E.g., "Cogito, ergo sum" - I think, therefore I am.
Et al. : Abbreviation of et alia, meaning "and others." For instance, used to indicate an unstated list of contributing authors following the main one or ones.
Et cetera: And so forth. Usually abbreviated etc.
Ex cathedra means "from the [bishop's] chair."
Ex Officio: "by right of office." Often used when someone holds one position by virtue of holding another.
Exempli gratia: "For example." Usually abbreviated to ‘e.g.’ and often confused with ‘i.e.’ Example: "Many real numbers cannot be expressed as a ratio of integers, e.g., the square root of two."
Flagrante Delicto: A legal term used to indicate that a criminal has been caught in the act of committing an offense (cf. corpus delicti). The colloquial “caught red-handed” or “caught in the act” are English equivalents.
Ibid.: This is the term (short for ibidem) used to provide an endnote or footnote citation or reference for a source that was cited in the preceding endnote or footnote. To find the ibid. source, one has to look at the reference right before it, and so ibid. serves a similar purpose to ditto marks.
Id est: Literally, "that is." Usually abbreviated ‘i.e.’ and often confused with ‘e.g.’ Example: "She won the race, i.e., she crossed the finish line first." The decision whether to use ‘i.e.,’ or ‘e.g.’ should be based on whether "that is" or "for example" would be used if written out in the sentence.
In toto: Entirely.
Ipso Facto: "by the fact itself"
In situ means "in place."
Non Sequitur: It does not follow. Often used as a debating term.
Per Diem: "Per day."
Post Mortem: "After death" - an autopsy.
Prima Facie: "On its first appearance," or "by first instance."
Pro Bono: "for the public good." Usually used of free representation by lawyers
Persona non grata is Latin for a person who is not welcome.
Prima facie means on its first appearance.
Pro forma is the Latin for "as a matter of form."
Pro rata is the Latin for "according to the amount calculated."
Pro tempore or pro tem is the Latin for "for the time (being)."
Quod erat demonstrandum (Q.E.D.) is the Latin for "that which was to be demonstrated."
Quod vide: Usually abbreviated q.v., this is a scholarly way of directing the reader to a reference.
Quasi: In some manner or to some degree. Similar to the prefix "semi."
Reductio ad absurdum is the Latin for "reduction to absurdity."
Requiescat in Pace or R.I.P. means "let him rest in peace."
Rigor mortis is the Latin for "stiffness of death."
Sine Qua Non: "Without which it could not be" ("but for"). It refers to an indispensable and essential action, condition, or ingredient.
Sub poena comes from the Latin for "under punishment." A subpoena is "a command to appear at a certain time and place to give testimony upon a certain matter."
Sui generis is the Latin for "of one's own kind" or "peculiar".
Summa cum laude is the Latin for "with highest praise."
Tabula Rasa is the Latin for "scraped tablet."
Verbatim: Word-for-word. Indicates a precise transmission of a phrase, discussion, or text.
Vice Versa: The other way around.
Videlicet : Usually abbreviated viz., this is translated as "namely."

Based on Wikipedia and other internet resources.