What is the Latin word for siesta?

The usual Latin words for “siesta” are merīdiātiō, merīdiō. The right choice depends on the sense; see the distinctions below.

English → Latin

“siesta” in Latin

merīdiātiōmidday nap, siesta merīdiōto take a siesta (mid-day nap)

The English word siesta itself goes back to Latin sexta.

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

siesta

meridiatio (the taking of a nap at noon, Cic., Divin., 2, 68, extr.): somnus meridianus (sleep at noon, as Plin., Ep 9, 40, 2). To take a siesta, meridiari (☞ meridiare is late); meridie conquiescere (☞ diffindere diem insiticio somno meridie is a conjectural reading, Varr., R.R., 1, 2, 5).

Quick answer

What is the Latin word for siesta?: The usual Latin words for “siesta” are merīdiātiō, merīdiō. 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.