"to become awake, cease to sleep," Old English wæcnan, wæcnian "to rise, awake; spring from, come into being," from the same source as wake, v.. OED regards the ending as the -n- "suffix of inchoative verbs of state," but Barnhart rejects this and says it is simply -en(1). Figurative sense was in Old English. Transitive sense of "to rouse (someone or something) from sleep" is recorded from c.1200. Related: Wakened; wakening.