Where does “onset” come from?

I cannot write this sentence because the etymology chain provided contains only English words cycling between "set" and "sett" with no older language sources, no stated meanings, and no clear path to the headword "onset." The rules require naming every language in order and weaving in the oldest meaning, neither of which is possible with this data.

onset (English): An attack; an assault especially of an army; The...

Definitions

  1. An attack; an assault especially of an army; The...

Ancestry of “onset”, step by step

StepLanguageWordMeaning
1Englishseṭof a root, having a final "i" sound in certain...
2EnglishseptA clan, tribe, or family, proceeding from a...
3EnglishsectAn offshoot of a larger religion; a group sharing...
4Middle EnglishsecteA variety or sort; a category with a...
5Old Frenchsectea sect in philosophy or religion
6Late Latinsectaa sect in philosophy or religion, a school,...
7Latinsequipresent active infinitive of sequor; follow, come...
8LatinsequorI follow, come or go after
9Proto-Italicsekʷōrfollow, come/go after
10Proto-Indo-Europeansékʷetorto be following
11Proto-Indo-Europeansekʷ-to follow; to see; to say

Words derived from “onset

Every word from Proto-Indo-European sekʷ-
onset — Etymology, Origin & Word History | Etymology Explorer