ovis

Ovis, ovis, f., third declension and an i-stem, so the genitive plural is ovium. The nominative and genitive singular look identical, which is normal for this pattern and means the case has to come from the surrounding words. Keep it apart from ovum, ovi, n., "egg": one letter, two very different farmyards.

The corpus is ecclesiastical, so most hits are the flock metaphor rather than actual livestock - the shepherd, the hundred sheep, the one that wandered off. The classical sense is simply the animal, valued for wool before meat. English keeps ovine and Spanish oveja comes straight down from it.