yì
different
Original meaning:
carry on the head
Phonosemantic compound. 廾 represents the meaning and 已 represents the sound. Simplified form of 異. Based on the original meaning "carry on the head", now written as 戴. The current meaning is a phonetic loan.
Evolution

Seal script
Shuowen (~100 AD)Regular script
ModernDefinitions
Sources
李学勤《字源》p.204-205