(CH3)3COH is a tertiary alcohol, so why is (CH3)3CNH2 not a tertiary amine? Grrr. Sometimes we just make it hard for students.
The term “tertiary amine” refers to the fact that there are 3 R groups (i.e., not hydrogen) attached to the nitrogen. (For the alcohol – tertiary means that the carbon attached to the -OH has 3 R groups attached)