The biological cousin that moreso performs or holds the role of an Aunt than a cousin to you.

Comes from the blending of Aunt + Cousin (Au from Aunt + Sin from Cousin)

Originates from the Midwest USA in 2020.
Hey, my Au-Sin is going to drop us off at the salon. Who? My cousin, but she's old enough to be my Aunt.
by Missing Apples 24 April 2, 2023
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