Origin of sign-in

First recorded in 1945–50; noun use of verb phrase sign in Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for sign-in

Contemporary Examples of sign-in

Word Origin and History for sign-in

1968, from the verbal phrase; see sign (v.) + in (adv.).

Online Etymology Dictionary, © 2010 Douglas Harper