see count.
see also tex system
Textile Resource (http://www.textile.org.uk)
The yards (or meters) per pound (ypp). So if you had a finished yarn that came up 890 ypp, one pound of yarn would equal 890 yards. The grist (or “count“) may range from 300 yds/lb to 3,000,000 yd/lb for a single filament of silk (theoretically)
Textile Links (http://www.textilelinks.com)