verb (past and past participle laid /leɪd/)
Old English lecgan, of Germanic origin; related to Dutch leggen and German legen, also to lie1
The verb lay means, broadly, ‘put something down’, as in they are going to lay the carpet. The past tense and the past participle of this verb is laid, as in they laid the groundwork or she had laid careful plans. The verb lie, on the other hand, means ‘be in a horizontal position to rest’, as in why don’t you lie on the floor? The past tense of this verb is lay (he lay on the floor) and the past participle is lain (she had lain on the bed for hours). Thus, in correct use, lay can be either the past tense of lie or the base form of lay. In practice many people make the mistake of using lay, laying, and laid as if they meant lie, lying, lay, and lain. Examples of incorrect use: why don’t you lay on the bed? (correct form is lie); she was laying on the bed (correct form is lying); he had laid on the floor for hours (correct form is lain).