生日用英语可以说为"birthday"。该词来源于中世纪拉丁语"nātālis diēs"，其中"nātālis"意为"relating to birth"，"diēs"意为"day"。下面是一些例句：

Today is my birthday. (今天是我的生日。)

I'm having a birthday party next week. (下周我有一个生日派对。)

I got a lot of birthday presents. (我收到了很多生日礼物。)

Happy birthday to you! (祝你生日快乐！)