moo of a cow, scream, to yell, dogs barking at each other
呍 centers on loud, rough vocal sounds: the moo of a cow, a scream, yelling, or dogs barking at each other. The common thread is a forceful, often animal-like outcry.
呍 combines 口 (mouth) with 云, which likely acts as a phonetic component. The character is used to represent various loud vocal sounds, but its exact historical development is uncertain.
A mouth 口 beside the cloud-like 云: imagine a cow mooing so loudly that its breath forms a cloud, or dogs barking until their voices rise like clouds.
For コウ, picture a cow letting out a loud moo that echoes like a gong: the cow's call sounds like コウ.