Lain is the past participle of the verb “lie,” meaning to rest in a horizontal position or to be situated somewhere. When something has lain in a place, it has been resting there for a period of time. For example, “The treasure had lain buried for centuries” or “The book had lain forgotten on the shelf all summer.”

This word often describes things that have remained undisturbed or unnoticed. Snow might have lain on the ground for weeks. A secret could have lain hidden in an old diary. Ancient ruins might have lain beneath the desert sand for thousands of years before archaeologists discovered them.

You'll typically see lain paired with “has,” “had,” or “have”: “The cat has lain in that sunny spot all afternoon.” It's easy to confuse this with “laid,” which comes from the verb “lay” (meaning to place something down). Remember: things that rest or recline have lain somewhere, while things you put down have been laid somewhere. If you've rested on the couch, you've lain there. If you've placed your backpack on the table, you've laid it there.