English

Noun

concentrator ‎(plural concentrators)

1. One who concentrates.
   • 1960, Dissertation Abstracts (volume 20, page 4007)

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

2. (telecommunications) A hub.
3. (mining) An apparatus for the separation of dry comminuted ore, by exposing it to intermittent puffs of air.

   (Can we find and add a quotation of Knight to this entry?)

4. (firearms) A 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.