HARK
hark, harken, hearken
(verb) listen; used mostly in the imperative
Source: WordNet® 3.1
Etymology
Verb
hark (third-person singular simple present harks, present participle harking, simple past and past participle harked)
(archaic) To listen attentively; often used in the imperative.
Noun
hark (plural harks)
(Scots) A whisper
Source: Wiktionary
Hark, v. i. Etym: [OE. herken. See Hearken.]
Definition: To listen; to hearken. [Now rare, except in the imperative form
used as an interjection, Hark! listen.] Hudibras. Hark away! Hark
back! Hark forward! (Sporting), cries used to incite and guide hounds
in hunting.
– To hark back, to go back for a fresh start, as when one has
wandered from his direct course, or made a digression.
He must have overshot the mark, and must hark back. Haggard. He
harked back to the subject. W. E. Norris.
Source: Webster’s Unabridged Dictionary 1913 Edition