Wurdahuzdą: Proto-Germanic dictionary

suffix noun masculine ja-stem forms relational adjectives and substantivized nominals denoting origin, descent, affiliation, or be-longing; ‘of, from, belonging to, descended from’ From Proto-Indo-European *-yó-s, with Sievers-law allomorph *-iyó-s, the masculine nominative singular of the relational adjective suffix *-yó-/*-iyó-. The original sense was broadly adjectival, ‘belonging to, connected with, characterized by’, from which the Germanic meanings ‘from, of, descended from, affiliated with’ developed. Cognate with Latin -ius, Ancient Greek -ιος, and Sanskrit -य, all continuing the same broad Indo-European relational/adjectival suffix Fulk 2018: 213–14 Krahe & Meid 1969: 70–72 Meier-Brügger 2003: 282–85 Ringe 2017: 326. Declension

The suffix varies as *-jaz /*-ijaz based on Siever’s Law: the basic *-jaz form is used after a “light” syllable (a short vowel followed by a single consonant), and otherwise, the form becomes *-ijaz.