In a blog on Italian language to which I subscribe the writer used the idiom "schiacciare un pisolino". I love to know how language comes about and am very curious to know why one would squash a little nap. Does anyone know the origin of this term?
E ’l capo tronco tenea per le chiome
Pesol con mano a guisa di lanterna
"Pisolino" is diminutive of "pisolo", derived from "pisolare" and this from "pesolo". The image is that of a heavy head, reclining, due to drowsiness. Note that these are all associated with "pensum", supine of "pendĕre", "to measure", whence "peso", "weight". Curiously "pennica" is from "pendicare", similar in etymology to "pisolare".
Agnolo Bronzino (1503-1572) used "stiacciare un sonnellino" in "Rime in burla. Lo spedale":
E dopo desinare un sonnellino
puoi stiacciare e poi desto trattenerti
con qualche altro malato tuo vicino.
According to Ivana Palomba, a user of Giorgio De Rienzo and Vittoria Haziel's forum Scioglilingua of Il Corriere della Sera, the origin of this expression can be found in the Florentine goldsmith tradition (!) where molten gold was removed from the mould and left to rest. They used the verb "stiacciare" to indicate the molten gold resting and solidifying ("stiacciare" is Florentine for Italian "schiacciare"). This happened at night, and in the meantime the goldsmith went to … squash a little nap.
I have no idea where Palomba got this interpretation and whether or not it is a reliable source: it seems a bit elaborate, but quite plausible. Anyway, I wasn't able to find a better source.