Where does “butterfly” come from?

Butterfly comes from Old English butorflēoge, whose ultimate origin and meaning are unknown.

butterfly (English): A flying insect of the order "Lepidoptera",...

Definitions

Step	Language	Word	Meaning
1	Middle English	buterflie	Alternative form of boterflye
2	Old English	buterflēoge	—
3	Old English	butere	butter
4	Proto-West Germanic	buterā	butter
5	Latin	būtȳrum	—
6	Ancient Greek	βούτυρον	butter
7	Ancient Greek	τυρός	cheese
8	Proto-Hellenic	tūrós	—
9	Proto-Indo-European	tuh₂-ró-s	—
10	Proto-Indo-European	tewh₂-	to swell; to crowd; to be strong

butterfly — Etymology, Origin & Word History | Etymology Explorer