Where does “involutional” come from?

involutional (English) comes from English involution, from Latin involūtiō, from Latin involvō, from Latin īn-, from Latin în, from Latin en, from Proto-Italic en, from Proto-Indo-European h₁én — in.

involutional (English): of or pertaining to involution; characterized by...

Definitions

of or pertaining to involution; characterized by...

Ancestry of “involutional”, step by step

Step	Language	Word	Meaning
1	English	involution	Entanglement; a spiralling inwards; intricacy; A...
2	Latin	involūtiō	—
3	Latin	involvō	to roll to or upon something
4	Latin	īn-	un-, non-, not
5	Latin	în	in, at, on, upon, from (space)
6	Latin	en	lookǃ beholdǃ; reallyǃ?; come onǃ
7	Proto-Italic	en	in
8	Proto-Indo-European	h₁én	in

Every word from Proto-Indo-European h₁én →Every word from Latin īn- →Every word from Proto-Italic en →