I. ˈnäk noun
( -s )
Etymology: Middle English nocke, nokke; akin to Old English hnocc penis, Middle Dutch nocke tip, summit, end of a yardarm, Old Norse hnuka to sit cowering, hnykill clew of yarn, tumor, Swedish nock, nocke pin, peg, end of a yardarm, Old Irish cnocc lump, hill, Latin nux nut — more at nut
1.
a.
(1) : either of two tips of horn fastened on the ends of a bow and having notches for holding the string
(2) : one of the notches cut in these or in the bow itself
b.
(1) : the part of an arrow having a notch for the bowstring whether as formerly a thick bulbous wooden end containing the notch or as now usually an attached fixture (as of horn or plastic) : the butt end of any arrow
(2) : the notch itself — see arrow illustration
2. obsolete : the cleft between the buttocks
3.
[probably from Dutch nok, from Middle Dutch nocke tip, summit]
: the upper fore corner of a boom sail or a staysail when cut with a square tack
II. transitive verb
( -ed/-ing/-s )
: to make a notch in or fit into or by means of a notch: as
a. : to slip (the eye of a bowstring) into a bow nock in bracing a bow
b. : to fit (an arrow) on the string of a bow
c. : to furnish (an arrow or bow) with a nock