1 a metal object that is used for locking a door, starting a car, etc 钥匙: Have you seen my car keys anywhere? 你有没有见过我的汽车钥匙？We need a spare key to the front door. 我们前门要配一把备用钥匙。a bunch of keys 一串钥匙

2 [usu.sing] the key (to sth) something that helps you achieve or understand sth 关键；要诀: A good education is the key to success. 良好的教育是成功的关键。

3 one of the parts of a piano, computer, etc that you press with your fingers to make it work （钢琴、计算机等的）键

4 a set of musical notes that is based on one particular note （音乐的）调: The concerto is in the key of A minor. 这是一首A小调协奏曲。 ☞picture at music 见music插图

5 a set of answers to exercises or problems 答案: an answer key 答案

6 a list of the symbols and signs used in a map or book, showing what they mean （地图或书本上的）符号表，图例