What is the Latin word for whereas?

The usual Latin words for “whereas” are quoniam, quandō̆, quandō̆quidem. The right choice depends on the sense; see the distinctions below.

English → Latin

“whereas” in Latin

quoniamsince, forasmuch, inasmuch as, now that quandō̆"When?"; "When".; ever, at any time, at some time, some day (especially following sī, num or ne)quandō̆quidemsince, since indeed, seeing that, inasmuch as, because

Riddle & Arnold A Copious and Critical English–Latin Lexicon, 1864

whereas

quoniam: quando: quandoquidem. [Vid: also SINCE] ☞ “Whereas” is often omitted, the adversative relation of the two clauses being denoted by the antithesis of the statements themselves; e.g., te enim dicere audiebamus, nos omnes adversarios putare, nisi qui nobiscum essent, te (= whereas you) omnes qui contra te non essent, esse tuos (Cic.).

Quick answer

What is the Latin word for whereas?: The usual Latin words for “whereas” are quoniam, quandō̆, quandō̆quidem. The right choice depends on the sense; see the distinctions below.

Entry from J. E. Riddle & T. K. Arnold, A Copious and Critical English–Latin Lexicon (rev. C. Anthon, New York: Harper, 1864), digitised by Fergus J. P. Walsh, CC BY-SA 4.0; Latin markup adapted by latindictionary.co.