jūn
unit of measure equivalent to thirty catties
Phonosemantic compound. 钅 represents the meaning and 匀 represents the sound. Simplified form of 鈞.
Evolution

Bronze script
Early Western Zhou (~1000 BC)
Seal script
Shuowen (~100 AD)
Clerical script
Cao Wei (Three Kingdoms: 222-280 AD)Traditional script
ModernSimplified script
ModernDefinitions