Webster's Revised Unabridged Dictionary · 1913

Ache

Ache ({not transcribed}) , noun

[Old English ache, Anglo-Saxon ace, ece, from acan to ache. See Ache, v. i.]

Continued pain, as distinguished from sudden twinges, or spasmodic pain. “Such an ache in my bones.” — Shakespeare

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

Ache ({not transcribed}) , intransitive verb

[Old English aken, Anglo-Saxon acan, both strong verbs, Anglo-Saxon 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. — Shakespeare
The sins that in your conscience ache. — Keble