1. apartment buildings without elevators, typically low-rise buildings where residents must walk up stairs to reach upper floors
Usage: plural form; real estate
2. customers who arrive without appointments or reservations
Usage: business context; informal

Examples

• Many young professionals live in walkups because they’re more affordable than luxury high-rises.
• The old neighborhood is full of charming walkups from the 1920s.
• She climbed four flights of stairs to reach her apartment in the walkup.
• The salon accepts walkups on weekdays but requires appointments on weekends.
• Most of their business comes from walkups rather than scheduled clients.
• The restaurant was busy with walkups during the lunch rush.