Where does “undersaturate” come from?

undersaturate (English) comes from English under, from Middle English under, from Old English under, from Proto-Germanic under, from Proto-Indo-European h₁entér, from Proto-Indo-European h₁en — in; in, inside.

undersaturate (English): To saturate too little

Definitions

To saturate too little

Ancestry of “undersaturate”, step by step

undersaturate traces back through two separate lines of ancestry.

via English under

Step	Language	Word	Meaning
1	English	under	In or at a lower level than; As a subject of;...
2	Middle English	under	under
3	Old English	under	under, beneath
4	Proto-Germanic	under	among, between; under, beneath; under
5	Proto-Indo-European	h₁entér	between
6	Proto-Indo-European	h₁en	in; in, inside

via English saturate

Step	Language	Word	Meaning
1	English	saturate	To cause to become completely impregnated, or...
2	Latin	saturatus	sated, satisfied
3	Latin	saturo	I fill to repletion, sate, satisfy
4	Latin	satur	full, sated; well-fed, replete; saturated
5	Proto-Indo-European	seh₂-	to satiate, satisfy

Every word from Proto-Indo-European h₁en →Every word from Proto-Indo-European h₁entér →Every word from Proto-Germanic under →