Where does “oier and terminer” come from?

oier and terminer (Middle English) comes from Old French terminer, from Latin terminō, from Latin Terminus, from Proto-Indo-European ter-, from Italian termine, from Latin terminus, from Proto-Italic termenos, from Proto-Indo-European térmn̥ — boundary, end.

Ancestry of “oier and terminer”, step by step

oier and terminer traces back through two separate lines of ancestry.

via Old French terminer

StepLanguageWordMeaning
1Old Frenchterminerto end; to terminate
2Latinterminōto mark off by boundaries, set bounds to; bound, limit
3LatinTerminusthe deity presiding over boundaries; a personification of the term terminus
4Proto-Indo-Europeanter-tender, weak; young creature
5Italiantermineend, close; limit, term, date, time; term, word
6Latinterminusa boundary, limit, end
7Proto-Italictermenos
8Proto-Indo-Europeantérmn̥boundary, end

via Anglo-Norman oyer

StepLanguageWordMeaning
1Anglo-NormanoyerAlternative form of oïr; hear
Every word from Proto-Indo-European térmn̥Every word from Proto-Italic termenosEvery word from Proto-Indo-European ter-
oier and terminer — Etymology, Origin & Word History | Etymology Explorer