Wiktionary
knurling
n. A knurled pattern vb. (present participle of knurl English)
Wikipedia
Knurling
Knurling is a manufacturing process, typically conducted on a lathe, whereby a pattern of straight, angled or crossed lines is cut or rolled into the material.
Usage examples of "knurling".
But then she went on, knurling her concentration in both fists so that she would not falter.
Her hands rested like a vulture's claws over the chair back, pale against the dark knurling of the grain.