twenty-firsts是twenty-first的复数
twenty-first
美
英
- n.21 岁生日；21 岁生日庆典
- 网络第二十一；第二十一的；第二十一日
n. | 1. somebody's 21st birthday, formerly marking the person's legal coming of age 2. someone’s 21st birthday, when they often have a party to celebrate the fact that they have become a full adult |