Wiktionary
headbox
n. 1 (synonym of headrail English) 2 A device for distributing a suspension of solids in water to a machine at a constant rate, or for retarding the rate of flow, as to a top-feed filter, or for eliminating by overflow some of the finest particles.
Usage examples of "headbox".
And, with a little extra effort, moonshine, brainstim, headboxes, needlework, or even a sleeve job.