What is the Latin word for fluid?

The usual Latin words for “fluid” are liquor, ūmor, aqua. The right choice depends on the sense; see the distinctions below.

English → Latin

“fluid” in Latin

liquorfluidity, liquidity; liquid, fluid ūmorliquid, fluid, humour; moisture aquawater

The English word fluid itself goes back to Latin fluō, through fluidus.

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

fluid

liquor (as substance, whose parts separate by themselves): humor (moistness, opposed to dryness; Vid: Cels., 4, 2, No. 4, extr.; Tac., Ann., 13, 57, 5): aqua (water, as the most common of fluids). ☞ latex is poetical only.

Quick answer

What is the Latin word for fluid?: The usual Latin words for “fluid” are liquor, ūmor, aqua. 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.