syn

Syn means son, and the plural is synowie, sons. In marriage and death entries a man is identified as syn followed by his father's name in the genitive, as syn Józefa i Agaty, son of Józef and Agata. The ending of the father's name changes, so Józefa here is the man Józef, not a woman.

In marriage records you will also see synem, the instrumental form used after między, between. Synowa means daughter-in-law, a different word.