Almost 40 million people in the United States have a disability, according to 2015 U.S. Census figures, but the language used around disabilities can be a mystery, fraught with acronyms and legalese. We’ve defined a few of those terms to help you navigate the world of disabilities.

In the Marketplace Weekend disability special, we are using person-first language, except when our guests prefer identity-first language. People-first language emphasizes the person instead of the disability. For example, “a woman with autism” instead of “an autistic woman.” Identity-first language uses the disability description first.

Ableism: Discrimination against people with disabilities if favor of able-bodied people.

Accommodations: Changes made in the workplace or school setting that level the playing field for people with disabilities. 

Acquired disability: A disability that occurs after birth, as by an accident.

ADA: The Americans with Disabilities Act of 1990. Legislation that prohibits discrimination against people with disabilities.

Comorbid: A concurrent condition or disability.

Congenital: A condition or disability present at birth.

Developmental disability: An impairment that begins during childhood developmental stages.

Disability: A physical or mental impairment that substantially limits one or more major life activities.

Early intervention: Services and supports for infants and young children with developmental delays or disabilities. Early intervention can have a “significant impact” on a child’s success in school and life, according to the Centers for Disease Control and Prevention.

IDEA: The Individuals with Disabilities Education Act of 2004. It ensures that students with disabilities are provided with a free appropriate public education (FAPE).

IEP: Individualized education program. A legal document that outlines a student’s classroom setting, services and goals for the year.

Inclusive classroom: A classroom in which special education students and general education students learn together.

Neurotypical: People with typical developmental abilities. The term is often used to describe individuals who are not on the autism spectrum.

Olmstead v. L.C.: A 1999 Supreme Court ruling that held that unjustified segregation of people with disabilities is discrimination and violates the ADA.

Rehabilitation Act of 1973: Prohibits discrimination against people with disabilities in federal programs and federal employment.

Section 504: Part of the Rehabilitation Act that ensures a child with a disability has equal access to an education, including the use of accommodations.

Services: Supportive measures and therapies provided to students with individualized education programs.

Specific learning disability: As defined by IDEA, a disorder that affects written or spoken language that make it difficult to listen, think, speak, read, write, spell and do mathematical calculations. It includes conditions such as perceptual disabilities, brain injury, minimal brain dysfunction, dyslexia and developmental aphasia.

SSDI: Social Security Disability Insurance. Benefits paid to people with disabilities who meet federal requirements.

TBI: Traumatic brain injury.

Sources: ADA.gov, Centers for Disease Control and Prevention, Equal Employment Opportunity Commission, Healthline, Individuals with Disabilities Education Act, Social Security Administration and Wrightslaw.