Lie and lay both have many definitions, but they’re most often confused where lie means to recline and lay means to put down. But the distinction is simple: Lay needs an object —something being laid—while lie cannot have an object. For example, you might lay a book on the table, lay a sweater on the bed, or lay a child in her crib.

Lie is a verb which means ‘to be in or put yourself into a flat position’. It is an irregular verb and it doesn’t take an object. The -ing form is lying and the past simple is lay. The -ed form, lain, is very formal and is rarely used: I love to lie on a beach and read. She lay on the bed and gazed at the ceiling, daydreaming.