Lay is often used where lie is considered standard, as in "I'm going to lay down for a quick nap." The use, which dates to the 14th century, troubled no one until the 18th, but since then, people who care about such things have tried to teach the rest of us that a person lies, not lays, down.
Lay commonly means to put or place someone or something down, as in Lay the bags on the table or I’m going to lay the baby in the crib. The sense of lie that’s often confused with lay means to be in or get into a reclining position—to recline, as in I just want to lie in bed for a few more minutes.
LAY definition: 1. to put something in especially a flat or horizontal position, usually carefully or for a…. Learn more.
Lay is used with some nouns in expressions about accusing or blaming someone. For example, if you lay the blame for a mistake on someone, you say it is their fault, or if the police lay charges against someone, they officially accuse that person of a crime.
To install certain building materials, laying one thing on top of another. To produce and deposit (an egg or eggs). The hen laid an egg. Did dinosaurs lay their eggs in a nest? To bet (that something is or is not the case). I'll lay that he doesn't turn up on Monday.
Definition of lay verb from the Oxford Advanced Learner's Dictionary. [transitive] to put somebody/something in a particular position, especially when it is done gently or carefully. lay somebody/something + adv./prep. He laid a hand on my arm. Relatives laid wreaths on the grave. She laid the baby down gently on the bed.