It sounds like it should be simple. It mostly is. Here is the answer straight from the law, the one place the question is actually settled.
People ask it more than you would think. A man does four years and gets out, and a decade later he is not sure the word applies to him. A woman serves twenty in the Guard and is told she is a veteran at the parade but not at the VA counter. The confusion is real, and it is not your fault. The rules live in one federal statute, and almost nobody reads it. So here it is.
The one-sentence answer
Federal law defines the word in 38 U.S.C. 101(2). A veteran is:
a person who served in the active military, naval, air, or space service, and who was discharged or released therefrom under conditions other than dishonorable.
Two pieces have to be true at once: you served on active service, and you left under conditions other than dishonorable. Everything else is just working out what those two phrases mean for your record.
What "active service" actually means
For someone who enlisted in the Army, Navy, Air Force, Marines, Space Force, or Coast Guard and served on full-time active duty, this part is settled. You served on active duty, so you served on active service. Done.
The National Guard and Reserve is where the line gets sharp, and where most of the confusion lives. Drill weekends and annual training, what the law calls active duty for training, generally do not by themselves make you a veteran under federal law. What counts is being called to federal active duty under Title 10 for something other than training, for example a deployment. Serve a real federal activation and come home with a clean discharge, and you are a veteran in full. The Congressional Research Service lays this out in plain terms in its report "Who Is a Veteran?" (CRS R47299).
One important exception cuts the other way: if a Guard or Reserve member is disabled or dies from an injury or disease in the line of duty during training, that period can count as active service. The definitions that govern all of this sit in 38 CFR 3.1.
The discharge part
The military issues five characters of service: honorable; general, under honorable conditions; other than honorable; bad conduct; and dishonorable. Honorable and general both clearly fall inside "conditions other than dishonorable," so they qualify.
The bottom three are not automatic disqualifiers and they are not automatic anything. When a discharge is other than honorable, bad conduct, or dishonorable, the VA runs what it calls a character of service determination to decide whether your service still counts as "other than dishonorable" for benefits. The governing rules were updated in 2024, see the Federal Register notice on character-of-discharge bars. If your paperwork says less than honorable, do not assume the door is closed. Get it looked at.
Veteran for the honor, veteran for the benefits
Here is the distinction that trips up good people: being a veteran and being eligible for a specific VA benefit are two different questions.
Most VA benefits add a service-length requirement on top of the basic definition. As a general rule you need to have served 24 continuous months, or the full period you were called up for, whichever is shorter, with exceptions for early discharge due to disability, hardship, or a service-connected condition. That minimum-duty rule lives in 38 U.S.C. 5303A. So you can absolutely be a veteran and still need to check the specific rules for health care, the GI Bill, or disability compensation one benefit at a time. Start at VA.gov eligibility.
There is also an honorary path. Federal law now recognizes Guard and Reserve members who served twenty years and earned a retirement as veterans for the sake of honor and recognition, even without a separate federal activation, but that honorary status does not by itself unlock VA benefits. The CRS report above walks through it. Translation: the title is yours; the benefits still follow their own rules.
How you prove it
The document that settles it is your DD Form 214 (for Guard service, often an NGB Form 22). It states your dates of service, your character of discharge, and your decorations, and nearly every benefit, state and federal, starts by asking for it. If you do not have a copy, request your records free from the National Archives at archives.gov/veterans. Keep a copy somewhere safe and a second copy somewhere else.
If your discharge is in the way
A less-than-honorable discharge is not always the final word, especially where it traces back to undiagnosed PTSD, a traumatic brain injury, military sexual trauma, or sexual orientation under repealed policy. You can apply to your service branch to upgrade or correct it. The VA publishes step-by-step instructions at va.gov/discharge-upgrade-instructions. It is a process, not a long shot, and it is worth starting.
The Alabama part
Alabama runs its own veteran programs through the Alabama Department of Veterans Affairs, and some state benefits set their own residency and service terms on top of the federal definition. The most useful door in this state is your County Veterans Service Officer. Every county has one, the service is free, and they will read your DD-214 with you and tell you exactly what you qualify for. Find your county office through the state department linked above.
The bottom line, and a warning
If you served on active service and left under conditions other than dishonorable, you are a veteran. Full stop. Whether a particular benefit is open to you is a second question with its own answers, and you do not have to guess at them alone.
And hear this plainly, because it is the kind of thing this site exists to say: you never have to pay anyone to file a VA claim. Accredited Veterans Service Officers and accredited representatives do it for free. The outfits advertising to take a cut of your back pay to "maximize" your claim are selling you something the law already gives you at no charge. Keep your money. Walk into the county VSO office.
Sourcing: the federal definition is 38 U.S.C. 101 and 38 CFR 3.1; the minimum-duty rule is 38 U.S.C. 5303A; the Guard, Reserve, and honorary-status nuances are summarized in the Congressional Research Service report "Who Is a Veteran?" (R47299). Eligibility and discharge-upgrade steps are from VA.gov; Alabama programs from the Alabama Department of Veterans Affairs. Not legal advice: this is general information about public law, not a determination of your individual eligibility. For that, take your DD-214 to your County Veterans Service Officer.