v.1. To cause someone or something to associate or cooperate with someone or something: The badges that the scouts wear affiliate them with different troops. The medical school is affiliated with the university.
2. To associate or cooperate with someone or something: This medical school affiliates with the large university.
3. To associate someone with something or someone as a subordinate, employee, or member. Used reflexively: After she finished law school, she affiliated herself with a good law firm.