An older textile mill term for an irregularity in a spun yarn, such as a localized thin spot lacking twist or a small tangled knot. These defects cause the yarn to break under tension during warping or weaving, leading to machine stops and fabric flaws. It is a clipped form of the word twitter, once common in woolen and cotton spinning.
Heard on the job
The warp keeps snapping because the yarn is full of twits from that bad roving batch.