Y-all-s Definition

pronoun
(nonstandard, regional, US) Possessive of y'all (standing in for your).
Here are y'all's tickets for the show tonight.
Wiktionary
(nonstandard, regional, US) Possessive of y'all (standing in for yours).
This drink's mine; Bill and Joe, those drinks are y'all's.
Wiktionary

Origin of Y-all-s

  • y'all +‎ -'s

    From Wiktionary