亦
yì · HSK 7
also
armpit pictograph: 大 figure with two marks under the arms, borrowed for also
亦 first drew a standing person 大 with a dot under each arm to point at the armpits. That original sense was later reassigned to 腋, and 亦 got reused as the function word meaning also or too.
亦 — person 大 with two dots marking armpits
亦 is a pictograph of a person (大) with two dots indicating the armpits, originally meaning 'armpit' — a sense later taken over by 腋. The character was borrowed phonetically to write the adverb meaning 'also' or 'likewise', which became its standard modern use.