1. to form or join a labor union
2. to cause workers to form or join a labor union

Examples

• The factory workers decided to unionize for better wages.
• Management tried to prevent employees from unionizing.
• Teachers in the district voted to unionize last year.
• The company feared that workers would unionize if conditions didn’t improve.
• Labor organizers helped the restaurant staff unionize.
• It took months for the warehouse employees to successfully unionize.