Friend who suddenly disappears, usually because of a new relationship.
We were tight until he met Lailia. Then he milk cartoned.
by trollope June 03, 2007
Subject of a missing person advertisement on the side of a milk carton, implying "disappeared without a trace".
Teamster Jimmy Hoffa was milk cartoned by the mob, and his body has never been found.
by HiTechHiTouch July 15, 2013