a long comfortable seat for two or more people to sit on 长沙发；长榻 
He was sprawled on the living-room couch watching TV. 他四肢舒展地躺在客厅沙发上看电视。 They sat down on the wide couch. 他们坐到宽大的长沙发上。
Extra ExamplesTopics Houses and homesb2She settled down to read on the huge, overstuffed couch. 她在软绵绵的大沙发里坐下读书。 The room contained an old worn couch. 房间里有一个破旧的老沙发。 You can sleep on the pull-out couch. 你可以睡在活动沙发床上。
Oxford Collocations Dictionaryadjective- comfortable
- comfy
- plush
- …
- lie (down) on
- recline on
- sink back on
- …
- cushion
- pillow
- potato
- …
- on a/the couch
a long piece of furniture like a bed, especially in a doctor’s office （尤指诊室内的）诊察台 She spends several hours a week on the psychiatrist's couch. 她每周都要看几个小时的精神科医生。
Oxford Collocations Dictionaryadjective- comfortable
- comfy
- plush
- …
- lie (down) on
- recline on
- sink back on
- …
- cushion
- pillow
- potato
- …
- on a/the couch
Word OriginMiddle English (as a noun denoting something to sleep on; as a verb in the sense ‘lay something down’): from Old French couche (noun), coucher (verb), from Latin collocare ‘place together’, from col- ‘together’ + locare ‘to place’.