Yours, Etc.: Origins and Uses of 8 Sign-Offs
1540s, from Middle French corsaire (15c.), from Provençal cursar, Italian corsaro, from Medieval Latin cursarius "pirate," from Latin cursus "course, a running," from currere "to run" (see current (adj.)). Meaning of the Medieval Latin verb evolved from "course" to "journey" to "expedition" to an expedition specifically for plunder.