A flight of stairs or a flight of steps
(Noun)
Synonyms:
  1. steps
  2. stairway
  3. staircase
  4. flight
  5. companionway
  6. stair
  7. escalator
  8. moving stair
  9. spiral-staircase
  10. open stairway
  11. closed stairway
  12. ascent