concentrator

plural concentrators

1. One who concentrates.

   Experienced classroom teachers are well acquainted with the attention-seeker, the shy girl, the aggressive boy, the poor concentrator, the slow student […]

   1960, Dissertation Abstracts, volume 20, page 4007

2. communicationsA hub.
3. businessAn apparatus for the separation of dry comminuted ore, by exposing it to intermittent puffs of air.
4. engineeringA frame or ring of wire or hard paper fitting into the cartridge case used in some shotguns, and holding the shot together when discharged, to secure close shooting; also, a device for slightly narrowing the bore at the muzzle for the same purpose.