fat, rump
膘 centers on fatty tissue, especially around the lower back or rump area. It refers to bodily fat or the fleshy hindquarters.
膘 combines the flesh radical ⺼ with 票, which likely contributes a phonetic element. The exact historical development is uncertain, but the character is associated with fatty parts of the body.
The flesh radical ⺼ on the left suggests body tissue, and 票 on the right can be thought of as a ticket or label. Imagine a butcher labeling the fatty rump cut with a ticket: 膘 is the fat on the rump.
For ヒョウ, picture a sumo wrestler with a huge, fatty rump stepping onto a hyō (俵, straw bale) during a match: hyō -> ヒョウ, and the bale supports his weighty rump.