knurl, there's no way to tell someone who hasn't had one of these events that they are real, but they are.
British Dictionary definitions for knurl
knurl
/nɜːl/
verb (transitive)
1.
to impress with a series of fine ridges or serrations
noun
2.
a small ridge, esp one of a series providing a rough surface that can be gripped
Word Origin
C17: probably from knur
Word Origin and History for knurl
n.
"hard excrescence," c.1600, probably a diminutive of Middle English knor "knot" (c.1400), related to gnarl, from Proto-Germanic *knur- (cf. German knorren "a knotty excrescence"). Related: Knurly.