nappy       
noun [ C ] UK uk/ˈnæp.i/ us/ˈnæp.i/ (US diaper)
 尿布
a square of thick soft paper or cloth that is fastened around a baby's bottom and between its legs to absorb its urine and solid waste
  disposable/reusable nappies 一次性/可重复使用的尿布 
 nappy cream 护臀霜 
 She was changing the baby's nappy. 她在给婴儿换尿布。 
 I knew William when he was still in nappies (= when he was a baby). 威廉还穿尿布的时候我就认识他了。