hobby的基本意思是“嗜好,业余爱好”,指人们在工作时间以外所从事的自己喜好的事情。hobby是可数名词,有复数形式,常用不定冠词修饰。

Reading children's literature is a hobby with him.他在业余时间读儿童文学消遣。
Stamp-collecting is a popular hobby.集邮是一种普遍的业余爱好。
Music is his chief hobby.音乐是他的主要业余爱好。
Gardening is one of his hobbies.园艺是他的业余爱好之一。
He didn't know what to do when he retired from work as he had no hobbies.他由于没有任何业余爱好,故退休之后就不知干些什么才好。
In the evening I like to sit down and pursue my hobbies.晚上我喜欢坐下来从事业余爱好。

hobby, pastime, recreation
这三个词的共同意思是“业余爱好”。其区别是:hobby是可数名词,一般指在室内或室外独自进行的活动,通常不剧烈(如集邮、下棋、弹奏乐器等),包括技术很高的活动或简单的动作; pastime指空余时间的娱乐活动,往往不具有什么内在的价值或意义,常指消遣,很多情况下可以和hobby通用; recreation强调改变环境以调节生活节奏或在紧张的工作之后放松一下。例如:
His favourable pastime〔hobby〕 is playing chess.他最喜欢的娱乐活动是下棋。
Going to the movies is the most popular pastime in the nation.在国内最流行的娱乐方式是看电影。
Walking, gardening and reading are quiet forms of recreation.散步、搞园艺、读书是安静的调节生活的方式。

［词源］  ＜hobbyhorse儿童可坐在上面前后摇动的木马