Concentrator

n.	1.	(Mining) An apparatus for the separation of dry comminuted ore, by exposing it to intermittent puffs of air.
	2.	(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.

(communications)

concentrator - A device that combines the data streams from many simultaneously active inputs into one shared channel in such a way that the streams can be separated after transmission. The concentrator's output bandwidth must be at least as great as the total bandwidth of all simultaneously active inputs. A concentrator is one kind of multiplexing device. For example, a concentrator may be used to connect 24 2400 bps TTYs to a host via a 57600 bps channel.