con·cen·trate / ˈkänsənˌtrāt/ • v. 1. [intr.] focus one's attention or mental effort on a particular object or activity: she couldn't concentrate on the movie. ∎  (concentrate on/upon) do or deal with (one particular thing) above all others: Luke wants to concentrate on his film career.2. [tr.] (often be concentrated) gather (people or things) together in numbers or in a mass to one point. ∎  [intr.] come together in this way: troops were concentrating at the western front. ∎  increase the strength or proportion of (a substance or solution) by removing or reducing the water or any other diluting agent or by selective accumulation of atoms or molecules.• n. a substance made by removing water or other diluting agent; a concentrated form of something, esp. food: apple juice concentrate.DERIVATIVES: con·cen·tra·tive / -ˌtrātiv/ adj.con·cen·tra·tor / -ˌtrātər/ n.

concentrate bring to a COMMON centre. XVII. f. †concentre (XVI) — F. concentrer; see CON-, CENTRE vb., -ATE 3.
So concentration XVII. concentric having a common centre XIV (rare before XVII; concentrical from XVI). — (O)F. concentrique or medL. -icus; see -IC.