“Lay” is a verb meaning to put or place something somewhere. It has a direct object. Its principal parts are “lay,” “laid,” “laid,” and “laying.”
What the words refer to is the action: If you set it (object) there, it is laying there. Lay it there. Lay it on the pillow.
If it is resting or reclining, it is lying there. Lie down. Lying down. Lie down, Sally. (Clapton had it wrong? Say it isn’t so!)
The internet is your friend, and can teach you many things besides how to make cute kitty memes. Quote from the wonderful website Get it Write: The verbs to lie and to lay have very different meanings. Simply put, to lie means “to rest,” “to assume or be situated in a horizontal position,” and to lay means “to put or place.” (Of course, a second verb to lie, means “to deceive,” “to pass off false information as if it were the truth,” but here we are focusing on the meaning of to lie that gives writers the most grief.)
As another great resource, in his July 7th, 2015 post on this subject for Writers’ Digest, Brian A. Klems gave us a useful chart:
Lay vs. Lie Chart
Infinitive Definition Present Past Past Participle Present Participle
to lay to put or place lay(s) laid laid laying
to lie to rest or recline lie(s) lay lain lying
This is where things get tense: present, past and future.
A ring lay on the pillow.
But I needed to rest:
So what this all boils down to is:
But just to confuse things:
A living body lies down and rests as is needed.
A dead body is cleaned up and laid out by other people, if said corpse was important to them. However, after having been laid out, said corpse is “lying in state“ to allow mourners to pay their respects.