Walk-up

Full definition of walk-up

Adjective

1. (of an apartment etc) reached by stairs rather than an elevator
2. (of a block of apartments) containing such flats
3. (of a service) for which no appointment is necessary

Noun

1. (US) Such an apartment or block.
• 2010, Christopher Hitchens, Hitch-22, Atlantic 2011, p. 228:I became the tenant of a walk-up on East Tenth Street, on the north side of Tompkins Square, found for me by the seemingly omni-connected Ian McEwan ....
2. (aviation) an informal visit to a control tower by a pilot, typically used as part of pilot training.