stairwell has definitions from the field of architecture
1
[ noun ] (architecture) a vertical well around which there is a stairway

Used in print

(E. Lucas Myers, "The Vindication of Dr. Nestor,"...)

The doctor , he noticed , was attempting a transverse movement towards the stairs , but before the movement could be completed a distinct and audible cluck ruffled the air in the hollow of the stair-well .

Related terms

well

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