Green’s Dictionary of Slang

(US drugs) butorphanol.

2003

Microgram Bulletin XXXVI:1 13: Tennessee veterinarian Timothy A. Williams [...] has had to rigorously restrict butorphanol prescriptions to clients with valid veterinary requirements, and then only after a valid patient-client-veterinarian relationship has been established, due to recreational abuse by the students. According to Dr. Williams, butorphanol is colloquially referred to by the students as ‘Torbo.’.