Lewis Short
per-callesco, callÅi, 3
* V. inch. n. and a. *
* Neutr., to become very hardened, very callous: civitatis patientia percalluerat,Cic. Mil. 28, 76.
* Act., to get a good knowledge of; in perf., to be well acquainted with, to know well, be well versed in: usum rerum,Cic. de Or. 2, 34, 137; so, disciplinas Stoicas et dialecticas,Gell. 1, 22, 7: leges,id. 20, 1, 20: quinque et viginti gentium linguas,id. 17, 17, 2.
Charlton T. Lewis, Charles Short, A Latin Dictionary