ache

Inherited from Middle English aken (verb), and ache (noun), from Old English acan (verb) (from Proto-West Germanic *akan, from Proto-Germanic *akaną (“to ache”)) and æċe (noun) (from Proto-West Germanic *aki, from Proto-Germanic *akiz), traditionally explained as from a Proto-Indo-European *h₂égos.

Cognate with Saterland Frisian eeke, ääke (“to ache, fester”), Low German aken, achen, äken (“to hurt, ache”), German Low German Eek (“inflammation”), North Frisian akelig, æklig (“terrible, miserable, sharp, intense”), West Frisian aaklik (“nasty, horrible, dismal, dreary”), Dutch akelig (“nasty, horrible”).

The verb was originally strong, conjugating for tense like take (e.g. I ake, I oke, I have aken), but gradually became weak during Middle English; the noun was originally pronounced as /eɪt͡ʃ/ as spelled (compare breach, from break). Historically the verb was spelled ake, and the noun ache (even after the form /eɪk/ started to become common for the noun; compare again break which is now also a noun). The verb came to be spelled like the noun when lexicographer Samuel Johnson mistakenly assumed that it derived from Ancient Greek ἄχος (ákhos, “pain”) due to the similarity in form and meaning of the two words.

From Middle English ache, from Old French ache, from Latin apium (“celery”). Reinforced by modern French ache.

Representing the pronunciation of the letter H.