We can easily think of ו being the copulative conjunction meaning and + noun שיוכם.
But in the dictionary we find שִֹיוּךְ, a noun that means belonging, appurtenance. We do not find שיוכם itself.
Centering this word: it is a word that belongs to IS-t2 type.
Look at ptr IS-t2-113
Meaning: and their belonging (of males)