Where does “-tas” come from?

-tas (Irish) comes from Irish -ta, from Irish -as, from Old Irish -as, from Proto-Celtic -assus, from Proto-Indo-European -ad-tus.

Ancestry of “-tas”, step by step

StepLanguageWordMeaning
1Irish-taadded to nouns to form adjectives; used to form...
2Irish-asNominal suffix, used to form abstract ideas or...
3Old Irish-asNominal suffix, used to form abstract ideas or...
4Proto-Celtic-assus—
5Proto-Indo-European-ad-tus—

Words derived from “-tas”

Every word from Proto-Indo-European -ad-tus →Every word from Irish -as →Every word from Irish -ta →
-tas — Etymology, Origin & Word History | Etymology Explorer