The person who changed the word benzene back to benzyl (this name was incorrectly used in this place up to this date) should note: Benzyl is C6H5CH2 and benzene is C6H6. In benzodiazepine, "benzo" stands for the benzene ring fused onto one side (i.e. bond) of 1,4-diazepine.

After "benzene ring" has been changed again to (incorrect) "(often substituted) phenyl group": Please note: 1. A phenyl group is a substituent (C6H5) linked by a single bond to another group. In benzodiazepines both the diazepine ring and the benzene ring share a common bond. 2. This make up for the parent compound of the benzodiazepine family; there can be substituents linked to either part of the bicyclic ring system. Ever taken a course in Organic chemistry?