Webster’s Revised Unabridged Dictionary · 1913
Nab
Nab (năb), n. [Cf. Knap, Knop, Knob.] 1. The summit of an eminence. [Prov. Eng.] Halliwell.
2. (Firearms) The cock of a gunlock. Knight.
3. (Locksmithing) The keeper, or box into which the lock is shot. Knight.
Nab, v. t. [imp. & p. p. Nabbed; p. pr. & vb. n. Nabbing.] [Dan nappe, or Sw. nappa.] To catch or seize suddenly or unexpectedly. [Colloq.] Smollett.