Where does “derein” come from?

derein (Old French) comes from Vulgar Latin deretranus, from Latin dē, from Latin post, from Latin poste, from Proto-Italic posti, from Proto-Indo-European pósti, from Proto-Indo-European pós — afterwards, post; by, at.

derein (Old French): last; final

Definitions

last; final

Ancestry of “derein”, step by step

Step	Language	Word	Meaning
1	Vulgar Latin	deretranus	to hinder
2	Latin	dē	of; concerning; about
3	Latin	post	behind; after, since, besides, except; behind,...
4	Latin	poste	ablative singular of postis
5	Proto-Italic	posti	behind, after
6	Proto-Indo-European	pósti	after
7	Proto-Indo-European	pós	afterwards, post; by, at

Every word from Proto-Indo-European pós →Every word from Proto-Indo-European pósti →Every word from Proto-Italic posti →