step-in

[ step-in ]
/ ˈstɛpˌɪn /

adjective

(of garments, shoes, etc.) put on by being stepped into.

noun

step-ins, panties, especially bias-cut panties with wide legs worn by women in the 1920s and 1930s.
any step-in garment.

Origin of step-in

First recorded in 1920–25; adj., noun use of verb phrase step in
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2020

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