• (America) IPA: /ˈstɛɹˌkeɪs/

staircase (plural staircases)

1. A flight of stairs; a stairway.
2. A connected set of flights of stairs; a stairwell.
   • 1914, Louis Joseph Vance, chapter III, in Nobody, New York, N.Y.: George H[enry] Doran Company, published 1915, OCLC 40817384 ↗:

     Turning back, then, toward the basement staircase, she began to grope her way through blinding darkness, but had taken only a few uncertain steps when, of a sudden, she stopped short and for a little stood like a stricken thing, quite motionless save that she quaked to her very marrow in the grasp of a great and enervating fear.

3. A set of locks (enclosed sections of waterway) mounted one above the next.

• French: escalier
• German: Treppe
• Italian: scalinata, tromba delle scale
• Portuguese: escadaria
• Russian: ле́стница
• Spanish: escalera

staircase (staircases, present participle staircasing; past and past participle staircased)

1. (transitive) To modify (a signal, a graph, etc.) so as to reduce a smooth curve to a series of discrete steps.