Glyph origin for 㐆 and Mnemonic for 殷
㐆 is a reversed 身 which could be a rotund man or pregnant woman, likely the latter in this context. I've never seen 㐆 being used alone before.
殷 is grand, abundant, or flourish. Getting pregnant with child would be a source of celebration back then, and 殳 represents a hand hitting something, likely a drum if we were to interpret the original meaning as &quot;grand music.&quot;
https://www.zdic.net/hans/%E6%AE%B7