Where does “onlych” come from?

onlych (Middle English) comes from Old English ānlīċ, from Old English ān, from Proto-West Germanic ain, from Proto-Germanic ainaz, from Proto-Indo-European óynos — one; single.

Ancestry of “onlych”, step by step

onlych traces back through two separate lines of ancestry.

via Old English ānlīċ

StepLanguageWordMeaning
1Old Englishānlīċonly
2Old Englishānlonely; entirely alone, solitary, single; one
3Proto-West Germanicainone
4Proto-Germanicainazone; some
5Proto-Indo-Europeanóynosone; single

via Old English ǣnlīċ

StepLanguageWordMeaning
1Old Englishǣnlīċlike; similar; equal
Every word from Proto-Indo-European óynosEvery word from Proto-Germanic ainazEvery word from Proto-West Germanic ain