The etymology is unknown, but the most plausible source on the basis of both semantics and historical phonology appears to be unattested Latin *c(h)araculum, which would have been a Latinized diminutive of Ancient Greekχάραξ(khárax, “stick”). This also provides a single, phonologically coherent source for the cognates Portuguese caralho, Spanish carajo and Catalan carall. Attempts to attribute Italian same-meaning **** to the same etymon fail on phonological grounds, as the /r/ of carajo (or its absence in ****) remains unexplained, and no Latin phonological sequence develops as both /x/ in Spanish and /tts/ in Italian.