Didn't know that Ravens were called that, I've heard a parliament of owls used as well. The "Murder" of crows dates back centuries to old English prose I've been told. Think it's just because of the cries they make together in flight, sounds like they are screaming bloody murder etc, and the fact they will kill their own wounded and scavenge anything. Apparently it's never officially been and still isn't the scientific term, and wasn't used for centuries until it became popular again.

Ever seen a murmuration of Starlings? Now that is worth a name