We say "please stand the chair up" to mean "to put the chair in a vertical position".
Do we say "please lay the chair down" to mean "to put the chair in a horizontal position" as shown in the picture?
English Language Learners Stack Exchange is a question and answer site for speakers of other languages learning English. It only takes a minute to sign up.Sign up to join this community
Yes, that's correct if you mean to lay it down on the ground or floor, like in your picture.
I think it's rare for people to do that to chairs on purpose, so you might get odd looks, no matter how you say it, until you confirm that you do indeed want that result. "Please tip the chair over and lay it down" or "please lay the chair down on its back [or on its side]" might more quickly and clearly confirm that you do want it in an abnormal position.
If you happen to mean to put it into that position, but on top of something else, you might want to specify both. For example, "please put the chairs on top of the tables, lying down".