Pronunciation: (ô'thu-rīz"),[key] —v.t.,-ized, -iz•ing. 1. to give authority or official power to; empower: to authorize an employee to sign purchase orders. 2. to give authority for; formally sanction (an act or proceeding): Congress authorized the new tax on tobacco. 3. to establish by authority or usage: an arrangement long authorized by etiquette books. 4. to afford a ground for; warrant; justify. Also,esp. Brit.,au'thor•ise".