VA Disability Glossary
VA disability glossary
The terms that actually decide VA claims, in plain English. Each one links to a deeper guide. Education only; we're not VA-accredited.
- Service connection
- VA's recognition that a disability was caused or aggravated by military service. It's the threshold every claim must clear before a rating and compensation follow. Learn more →
- Nexus
- The documented medical link between a current condition and military service. A nexus is the element most denied claims are missing — a diagnosis and a service event aren't enough without the connection between them. Learn more →
- Secondary service connection
- A condition caused or aggravated by an already service-connected disability, claimable under 38 CFR 3.310 even though it didn't begin in service — for example, sleep apnea secondary to PTSD. Learn more →
- Aggravation
- When a service-connected condition permanently worsens a condition you'd otherwise have. VA compensates the degree of worsening over the condition's baseline level, not the whole condition. Learn more →
- Presumptive condition
- A condition VA presumes is linked to service for veterans who served in a covered location during a covered period — so you skip proving exposure and nexus. The PACT Act expanded these lists. Learn more →
- PACT Act
- The Honoring our PACT Act of 2022, the largest expansion of VA benefits for toxic-exposed veterans in decades — adding presumptive conditions, covered locations, and toxic-exposure screening. Learn more →
- TERA (Toxic Exposure Risk Activity)
- VA's finding that your service involved toxic exposure. It is not a presumptive — it's the path for off-list conditions, triggering VA's duty (38 U.S.C. 1168) to obtain a nexus medical opinion. Learn more →
- TDIU (Individual Unemployability)
- Total Disability based on Individual Unemployability — being paid at the 100% rate while rated below 100%, when service-connected conditions prevent substantially gainful work (38 CFR 4.16). Learn more →
- Combined rating (VA math)
- VA doesn't add ratings — it combines them with whole-person math and rounds to the nearest 10%. That's why two 50% conditions combine to 75% (rounded to 80%), not 100% (38 CFR 4.25). Learn more →
- Bilateral factor
- An extra factor VA adds when disabilities affect both arms or both legs: it combines the paired ratings, adds 10% of that value, then combines with the rest (38 CFR 4.26). Learn more →
- Diagnostic code
- The number VA uses to identify a condition in the rating schedule (38 CFR Part 4) — for example, 6260 for tinnitus or 9411 for PTSD. The code sets the criteria that decide your percentage. Learn more →
- Effective date
- The date VA uses to start your benefits — generally the date you filed (with exceptions). It drives how far back your retroactive pay reaches (38 CFR 3.400). Learn more →
- Back pay (retroactive pay)
- The lump sum for the period between your effective date and the date VA grants the claim. The earlier the effective date and the higher the increase, the larger the back pay. Learn more →
- P&T (Permanent and Total)
- A 100% rating that VA considers both total and permanent (not expected to improve), which removes future re-examinations and unlocks additional benefits for the veteran and family. Learn more →
- C&P exam
- The Compensation & Pension exam VA orders to evaluate a claimed condition. Many claims are won or lost here — describe your worst days honestly and don't minimize. Learn more →
- DBQ (Disability Benefits Questionnaire)
- A standardized form that captures the severity of a condition for rating. VA pulled most public DBQs in 2020, but private providers can still complete them. Learn more →
- FDC (Fully Developed Claim)
- A faster VA filing track where you submit all evidence up front and certify nothing is missing. An FDC is not a nexus letter or a DBQ — it's a processing lane. Learn more →
- Character of discharge (COD)
- VA's own determination of whether your service was honorable for VA-benefit purposes — separate from a discharge upgrade. An other-than-honorable discharge doesn't automatically bar benefits. Learn more →