Where does “extrim” come from?

extrim (Latin) comes from Latin exter, from Proto-Italic *eksteros.

Ancestry of “extrim”, step by step

extrim traces back through two separate lines of ancestry.

Step	Language	Word	Meaning
1	Latin	exter	On the outside, outward, external, outer; Of...
2	Proto-Italic	*eksteros	—

Step	Language	Word	Meaning
1	Latin	secus	otherwise, to the contrary; differently; by,...
2	Proto-Indo-European	sekʷ-	to follow; to see; to say