un·ion·ize \ˈ ̷ ̷ ̷ ̷ˌnīz\transitive verb (-ed/-ing/-s) Usage: see -ize Etymology:union (I) + -ize : to cause to become a member of or subject to the rules of a labor union < planned to unionize the shop > : form into a labor union < unionizing previously unorganized groups >