Webster's Revised Unabridged Dictionary · 1913

Knurl

Knurl (nûrl) , noun

[See Knar, Gnar.]

A contorted knot in wood; a crossgrained protuberance; a nodule; a boss or projection.
2.
One who, or that which, is crossgrained.

Knurl (nûrl) , transitive verb

To provide with ridges, to assist the grasp, as in the edge of a flat knob, or coin; to mill.