black ox, yak
犛 refers to a black ox or a yak, a large bovine animal. The two meanings are closely related, both describing a type of cattle.
犛 is a phono-semantic compound: 牛 (cow/ox) provides the meaning, while the upper part (originally 氂 without the 毛) likely contributed the sound. The exact historical development of the upper component is uncertain.
The bottom part is 牛 (cow), and the top looks like a shelter (厂) with a stick (攵) and a tree (木). Imagine a sturdy black yak under a rough shelter, tied to a tree with a stick, representing a strong bovine.
For ボウ, picture a bow (ボウ) tied around the yak's horns, making it look like a black ox ready for a festival. The bow sound cues ボウ.