adv. , n. /down"stairz"/ ; adj. /down"stairz'/ , adv.
1. down the stairs.
2. to or on a lower floor.
adj.
3. Also, downstair . pertaining to or situated on a lower floor, esp. the ground floor.
n.
4. ( used with a sing. v. ) the lower floor or floors of a building: The downstairs is being painted.
5. the stairway designated for use by people descending: Don't try to go up the downstairs.
[ 1590-1600; DOWN 1 + STAIR + -S 3 ]