unionized

Unionized has two meanings depending on pronunciation.

With stress on the second syllable (yoon-YUN-ized), it describes workers who have organized into a labor union: The factory workforce unionized last year, unionized teachers.

With stress on the first syllable (un-EYE-uh-nized), it's a chemistry term meaning not ionized—having no electrical charge: unionized molecules pass through cell membranes more easily.