what is a veteran?

My sister talks highly of herself, calling herself a veteran. 
All she did was go to basic. Then she got a dishonorable discharge just because she didn't want to be in the army anymore. She talks about how she served this country. She gets veteran benifits. How? I think she's lying to someone. 
I always thought a veteran was someone who has gone over seas and fought or have actually SERVED in the army. Not someone who has just gone to training and went home. She thinks she deserves more than everyone else for her "service" 
She also claims to have ptsd from basic training. And calls herself a soldier. She told me with her own mouth that she just didn't want to be deployed because she knew she would die.