Past tense of 'lay,' meaning placed something down; can also mean relaxed or established (as in 'laid-back').
From Old English 'lecgan,' the word has changed meaning slightly—'lay' originally meant to make something lie, versus 'lie' which meant to recline, a distinction many English speakers now confuse.
The 'lay versus lie' confusion is so common that some linguists predict these two words might eventually merge in English, making the distinction disappear entirely within a few generations.
Complete word intelligence in one call. Free tier — 50 lookups/day.