dime /daɪm/ BrE AmE noun [countable]
[ Date: 1300-1400 ; Language: Old French ; Origin: 'tenth part' , from Latin decima ]
1 . a coin of the US and Canada, worth one tenth of a dollar
2 . a dime a dozen American English informal very common and not valuable SYN ten a penny British English :
PhDs are a dime a dozen nowadays.