from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A knob, knot, or other small protuberance.
- n. One of a series of small ridges or grooves on the surface or edge of a metal object, such as a thumbscrew, to aid in gripping.
- transitive v. To provide with knurls; mill.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A contorted knot in wood.
- n. A crossgrained protuberance; a nodule; a boss or projection.
- n. A lined or crossgrained pattern of ridges or indentations rolled or pressed into a part for grip.
- v. To roll or press a pattern of ridges or indentations into a part for grip.
from the GNU version of the Collaborative International Dictionary of English
- n. A contorted knot in wood; a crossgrained protuberance; a nodule; a boss or projection.
- n. One who, or that which, is crossgrained.
- transitive v. To provide with ridges, to assist the grasp, as in the edge of a flat knob, or coin; to mill.
from The Century Dictionary and Cyclopedia
- n. A knot; a hard substance; a nodule of stone; a protuberance in the bark of a tree.
- n. A deformed dwarf; a humpback.
- n. In photography, a milled-edge roller used for dotting and softening outrunning lines and making dark spaces lighter.
Probably diminutive of knur.(American Heritage® Dictionary of the English Language, Fourth Edition)
knur + -le (“diminutive”), from Middle English knar ("knot in wood"), earlier sense “a stone”, of Unknown origin. (Wiktionary)