n (1)钥匙(shaped metal device used to open or close a lock，wind a clock，start or stop a car engine，etc)[C]：a door/car～门/汽车钥匙;an ignition～ 点火开关钥匙;the～to the front door 前门钥匙;have a～cut/made to fit a lock 给锁配一把钥匙;put/turn the～in the lock 把钥匙塞进锁孔/转动钥匙;〖同〗opener，passkey;

(2)转柄(shaped device used for turning a part in a machine，etc)[C]：a～to open this valve/turn off the central heating 打开这个阀门/关闭集中供暖装置的开关;a～for winding the clock 给这个钟上弦的钥匙;

(3)键(button that one presses to make an instrument or machine work)[C]：the～s of a piano/a typewriter 钢琴/打字机键;a row of black and white～s 一排黑白琴键;

(4)音调，主音(chief note of a piece of music)[C]：the～of D D调;a symphony in the ～of C minor 一首C小调交响曲;a sonata in the ～of E flat minor 一首降E小调奏鸣曲;sing in a low～低调吟唱;～signature 乐谱的调号;〖同〗scale，mode;

(5)基调，调子(mood or characteristic style as of expression or thought)[C]：all in the same～千篇一律;report the event/treat this whole affair in a low～以低调报告事件/对待这个事情;

(6) 关键，要诀(thing that explains sth or provides an answer or solution)[C，通常sing] [N(to)]：the～to the problem/murder/an improvement of their living conditions 问题/谋杀案/他们生活条件改善的关键;the～to one's success or failure 决定某人成败的关键;The Bosporus is the～to the Black Sea. 博斯普鲁斯海峡是黑海的咽喉。～money (房租之外的)小费;

(7) 解题，解答，图例说明(answers to exercises，problems or question)[C]：a～for the use of teachers only/to the grammar exercises 专供教师用的题解/语法练习答案;a book of English tests，complete with～附题解的英语测试题;the～to a puzzle 谜底;provide the～to the mystery 提供谜底;The～on the map explains the meanings of the different colours，lines，etc.地图上的图例说明了不同颜色、线条等的意义。〖同〗solution，explanation，answer;

→′keyboard n 键盘; v 操作键盘;(操纵键盘)将资料输入计算机;′keyboarder n 操纵计算机键盘的人;′keyhole n 锁眼;钥匙孔;′keynote n 基调;主音;′keypad n 小型键盘;′key-ring n 钥匙环(圈);′keystone n 拱顶石;根本;关键;

adj 关键性的，极重要的(chief，major，important or essential)[作attrib]：a～position/industry/man 险要位置/主要工业/关键性人物;a～battle in the war/issue in the forthcoming election 战争中的重要一役/即将来临的选举中的关键性问题;the～word of a sentence 句子中的关键词