Meaning of "lie down" in Essential American English Dictionary

lie down

phrasal verb with lie us /lɑɪ/ us /lɑɪ/ verb, verb (present participle lying, past tense and past participle lay, past participle lain, present participle lying, past tense and past participle lied)

A2 to move into a position in which your body is flat, usually in order to sleep or rest:

I’m not feeling well – I’m going to lie down.

(Definition of “lie down” from the Webster's Essential Mini Dictionary © Cambridge University Press)