di ‧ a ‧ per /ˈdaɪəpə $ ˈdaɪpər/ BrE AmE noun [countable]
[ Date: 1300-1400 ; Language: Old French ; Origin: diapre 'fine cloth' , from Medieval Greek diapras 'pure white' ]
American English a piece of soft cloth or soft paper that is put between a baby’s legs and fastened around its waist to hold liquid and solid waste SYN nappy British English :
I changed her diaper.