Lewis Short
Picti (noun M) : pingo, the painted people
* A people of Britain, the Picts or ancient Caledonians (so named from their practice of tattooing themselves), Amm. 20, 1, 1; Claud. III. Cons. Hon. 54; id. Laud. Stil. 2, 254.
Charlton T. Lewis, Charles Short, A Latin Dictionary