It’s easy to get these two words confused. And there are a few wrinkles that make it even more confusing.
But let’s start with the basics:
Lie means to get into or be a reclining position. It’s something you do yourself. It can also refer to an object (or objects) at rest.
- I’m going to lie down for a nap.
- She likes to lie in the sun.
- And old quilt lies on our bed.
Lay means to put something down in a horizontal position or a position of rest. It’s something you do to something (or occasionally someone) else.
- Every evening I lay out the clothes I’m going to wear the next day.
- I’m going to lay the baby down for a nap.
- Could you lay the rug by the door?
Now that you have that down (hopefully), let me introduce the wrinkle: the past tense (something that happened in the past).
The past tense of lie is lay. (Is that confusing or what?)
- I lay down for a nap at 2 pm and didn’t wake up until 4.
- After working out I just lay there, too tired to get up.
- Fresh snow lay on the ground that morning.
The past tense if lay is laid.
- I laid the baby down for a nap an hour ago.
- I can’t remember where I laid the paper.
- He laid the book on the desk.
There’s also something called “past participle.” The easiest way to explain “past participle” is the past tense with a helping verb.
The past participle if lie is lain.
- Many times I have lain on this bed.
- She had just lain down when the phone rang.
- The newspaper has lain there all week.
The past participle of lay is laid (same as the past tense in this case).
- I have laid tile in this house.
- Our hen has laid an egg every day this week.
- We have laid that subject to rest.
Now to add yet another wrinkle to this. The past tense of lie is different depending on the meaning of the word. It’s one of only a few words in the English language where this is the case. If you use the word lie to mean “to tell a falsehood,” then the past (and also past participle) is lied. So you would say
- I don’t like to lie to people
- I’m sorry I lied to you.
- He has lied about his age before.
Hopefully you'll remember those examples the next time you ask yourself, "Should I say 'lie' or 'lay'?"