42 U.S.C. § 12102 — Definition of disability

As used in this chapter:
(1) Disability
"Disability" means, for an individual:
(A) a physical or mental impairment that substantially limits one or more major life activities;
(B) a record of having had such an impairment; or
(C) being regarded as having such an impairment (as explained in paragraph (3)).

(2) Major life activities
(A) In general. Major life activities include, but aren't limited to: caring for oneself, doing manual tasks, seeing, hearing, eating, sleeping, walking, standing, lifting, bending, speaking, breathing, learning, reading, concentrating, thinking, communicating, and working.
(B) Major bodily functions. A major life activity also includes a major body function working properly — including the immune system, normal cell growth, and the digestive, bowel, bladder, neurological, brain, respiratory, circulatory, endocrine, and reproductive systems.

(3) Regarded as having such an impairment
(A) A person meets the "regarded as" test if they show they were subjected to an action this chapter prohibits, because of an actual or perceived physical or mental impairment — whether or not that impairment actually limits, or is perceived to limit, a major life activity.
(B) But this doesn't apply to impairments that are transitory and minor. A "transitory" impairment is one with an actual or expected duration of six months or less.

(4) Rules of construction regarding the definition of disability
The definition of "disability" in paragraph (1) must be read using these rules:
(A) The definition must be read to favor broad coverage of individuals, to the maximum extent this chapter's terms permit.
(B) "Substantially limits" must be read consistent with the findings and purposes of the ADA Amendments Act of 2008.
(C) An impairment only needs to substantially limit one major life activity to count — it doesn't need to limit others too.
(D) An impairment that comes and goes, or is currently in remission, still counts as a disability if it would substantially limit a major life activity when active.
(E)
(i) Whether an impairment substantially limits a major life activity is decided without regard to how much better certain mitigating measures make it — including medication, medical supplies, equipment, low-vision devices (not counting ordinary eyeglasses or contact lenses), prosthetics, hearing aids or cochlear implants, mobility devices, or oxygen equipment; use of assistive technology; reasonable accommodations or auxiliary aids; or learned behavioral or adaptive neurological modifications.
(ii) The one exception: the effect of ordinary eyeglasses or contact lenses IS considered when deciding whether an impairment substantially limits a major life activity.
(iii) In this subparagraph: "ordinary eyeglasses or contact lenses" means lenses meant to fully correct visual acuity or eliminate refractive error. "Low-vision devices" means devices that magnify, enhance, or otherwise augment a visual image.