bucranium
The depiction of the head of an ox, as ornamental flourishes in architectural works.
On the second side of the gem, we see the victim, a running goat, and on the third side the symbol of sacrifice, the bucranium.
Where it comes from
From Latin būcrānium, from Ancient Greek βουκράνιον (boukránion).
Adapted from the Wiktionary entry bucranium (CC BY-SA 4.0).