walk-inEnglishOxford New American Dictionarywalk-in /ˈwôk ˌin, ˈwɔk ˌɪn / ▸ adjective 1 (especially of a storage area) large enough to walk into: a walk-in closet. 2 (of a service) available for customers or clients without the need for an appointment: a walk-in clinic. ▸ noun a walk-in customer or a walk-in storage area.