(名詞) (兒語) 小便，尿尿，小號。
- Kid: I have to go to the bathroom. (我要上廁所)
- Parent: Number one or number two? (小號還是大號?)
- Kid: Number one. (小號)
(名詞) 自己，自我。
- I always look out for number one. (我一向維護自身的權益)
註：Look out for number one 意為「保護自身利益」，如 You’ve got to look out for number one － no one else will. (你必須維護自身的利益，別人可不會為你著想)