bike

Origin

Clipping of bicycle. First attested in 1882. One explanation for the form with /k/ is that bicycle was parsed to bi(cy)c(le). An alternative explanation is that it was parsed to bic(ycle) but since speakers are aware of a general /k/~/s/ alternation (as in electric ~ electricity etc.), the softened /s/ was restored to a default /k/ when the “ending” -ycle was dropped. Similar cases are merc /mɜɹk/, spec /spɛk/ for mercenary, specify. It seems unlikely, however, that this process is purely phonological and not at least partially based on the spelling ⟨c⟩.