1630s, "to bring or come to a common center," from concenter (1590s), from Italian concentrare, from assimilated form of Latin com "with, together" (see con-) + centrum "center" (see center (n.)).
Meaning "condense" is from 1680s; that of "intensify the action of" is from 1758. Sense of "mentally focus" is from 1860s, on the notion of "concentrate the mind or mental powers." Related: Concentrated; concentrating.