→ Proto-Brythonic: *pɨsk(see there for further descendants)
References
“piscis”, in Charlton T. Lewis and Charles Short (1879) A Latin Dictionary, Oxford: Clarendon Press
“piscis”, in Charlton T. Lewis (1891) An Elementary Latin Dictionary, New York: Harper & Brothers
piscis in Charles du Fresne du Cange’s Glossarium Mediæ et Infimæ Latinitatis (augmented edition with additions by D. P. Carpenterius, Adelungius and others, edited by Léopold Favre, 1883–1887)
piscis in Gaffiot, Félix (1934) Dictionnaire illustré latin-français, Hachette.
Carl Meißner, Henry William Auden (1894) Latin Phrase-Book, London:Macmillan and Co.
to live on meat, fish, by plunder: vivere carne, piscibus, rapto (Liv. 7. 25)