downstairs
UK[ˌdaʊnˈsteəz]US[ˌdaʊnˈsterz]
adv
to or on a lower floor of a building, especially the ground floor
adj
located on a lower floor of a building
n
the lower floor of a building, especially the ground floor
Morpheme Breakdown
down
stairs
down
lower position
stairs
series of steps
Etymology
the word "downstairs" is a transparent compound formed from two old english elements. "down" originates from the old english "dūne", related to "dūn" (hill), and evolved to signify movement or position toward a lower level. "stairs" derives from the old english "stǣger", meaning a series of steps for ascending or descending. the compound "downstairs" logically combines these concepts to denote the direction toward or the location on the lower level accessible by a staircase, a meaning that has remained consistent since its formation in the late 16th century.
Analysis
Structure: down (lower position) + stairs (series of steps)
down: from old english "dūne", a shortened form of "of dūne" meaning "from the hill". it functions as an adverb/adjective indicating a lower position or direction.
stairs: from old english "stǣger", meaning "a flight of steps, staircase". it functions as a noun referring to the structure for moving between levels.
Examples
she ran downstairs to answer the front door.
the downstairs bathroom is currently being renovated.
we've decided to rent out the downstairs as a separate apartment.