To be a "veteran" under Massachusetts law a person must have a last discharge or release under honorable conditions and have either (1) 180 days of regular active duty service, or (2) 90 days of active duty service, one day of which is during "wartime" (except for Vietnam I which requires 180 days of active duty service).
Veteran status does not derive from training in the army National Guard or Air National Guard or for training as a reservist in the armed forces of the United States, although Massachusetts does offer some benefits for such service.
Proof that you are a Veteran. To apply for veteran benefits you generally must furnish proof of your service record, such as by showing discharge papers. If you (or your next of kin) do not have such records you can apply for copies.