Ach { , Ache } (?), n. [F. ache, L. apium parsley.] A name given to several species of plants; as, smallage, wild celery, parsley. [Obs.] Holland.

Ache (?), n. [OE. ache, AS. æce, ece, fr. acan to ache. See Ache, v. i.] Continued pain, as distinguished from sudden twinges, or spasmodic pain. "Such an ache in my bones."Shak.

☞ Often used in composition, as, a headache, an earache, a toothache.

Ache (?), v. i. [imp. & p. p. Ached (?); p. pr. & vb. n.Aching (?).] [OE. aken, AS. acan, both strong verbs, AS. acan, imp. ōc, p. p. acen, to ache; perh. orig. to drive, and akin to agent.] To suffer pain; to have, or be in, pain, or in continued pain; to be distressed. "My old bones ache." Shak.

The sins that in your conscience ache. Keble.

-- Webster's unabridged 1913