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Reference

Accessibility glossary.

Plain-language definitions of the terms you'll meet in accessibility laws, standards, plans and drawings, checked against official sources as of October 2026.

PRISM Accessibility Consultants · Reviewed October 2026

These terms come up in Ontario and federal accessibility law, building standards, digital guidelines and CMHC's MLI Select program. The definitions are written to be understood, not quoted, so follow the links for the official wording. They are general information, not legal advice.

A · B · C · D · H · I · L · M · O · P · R · S · T · U · V · W

A

Accessibility
How well people with disabilities can find, reach, use and take part in a place, service, document, website or job, on an equal footing with others. Good accessibility removes barriers before anyone has to ask. See what an accessibility checklist misses.
Accessibility audit
A structured review of a building, service, website or organization that identifies barriers and sets priorities for removing them. PRISM's audits look at physical spaces, programs, communications, digital tools and policies together.
Accessibility for Ontarians with Disabilities Act (AODA)
Ontario's accessibility law, passed in 2005 with the goal of an accessible Ontario by 2025. Its standards, set out in the IASR, apply to organizations in Ontario with at least one employee, with more duties for larger ones. Read AODA essentials for Ontario organizations.
Accessibility plan
A written plan for how an organization will find, remove and prevent barriers. Under the AODA, the public sector and organizations with 50 or more employees keep a multi-year plan, post it online and review it at least every five years. Under the Accessible Canada Act, federally regulated organizations update theirs at least every three years.
Accessible Canada Act (ACA)
Federal law, in force since July 11, 2019, that aims to make Canada barrier-free by January 1, 2040. It applies to federally regulated organizations, such as federal departments, banks, telecommunications companies and federal transportation providers, and Accessibility Standards Canada develops standards under it. Summary of the Accessible Canada Act.
Accommodation
A change to a rule, practice, space or way of doing things so that a person with a disability can take part fully. Under Ontario's Human Rights Code, accommodation should respect dignity, meet the person's individual needs and support their full participation. See duty to accommodate and Making workplace accommodation work.
Alt text (alternative text)
A short description of an image that screen readers read aloud. It should convey the image's purpose, not every detail, and purely decorative images are marked so they're skipped. W3C alt decision tree.
Alternate formats
Versions of information that people with disabilities can use, such as large print, braille, audio, or accessible electronic files like HTML or Word. Ontario's rules call them accessible formats, and organizations must provide them on request, in a timely way and at no extra cost.
American Sign Language (ASL)
A complete visual language with its own grammar, and one of the most common sign languages in Canada. The Accessible Canada Act recognizes ASL, LSQ and Indigenous sign languages as the primary languages of Deaf people in Canada.
Assistive device
Equipment a person with a disability uses to help with daily living, such as a wheelchair, screen reader or oxygen tank. Ontario's customer service rules require organizations to allow assistive devices. How to make customer service accessible.
Assistive listening system
Equipment that carries sound from a microphone directly to a listener's hearing aid, cochlear implant or headset, cutting out background noise. Hearing loops and FM systems are common examples at counters, meetings and events.
Assistive technology
Hardware or software that helps people with disabilities use computers, phones and other technology, such as screen readers, magnifiers, speech input and switches. Accessible websites and documents are built to work with it.
Audio description
Narration that describes important visual details in a video, such as actions or on-screen text, that the soundtrack alone doesn't convey. WCAG 2.2 Level AA asks for it in prerecorded video. Ontario's website rules currently exempt it, but it remains good practice.

B

Barrier
Anything that hinders the full and equal participation of people with disabilities. The Accessible Canada Act includes physical, architectural, technological and attitudinal barriers, and barriers created by information, communications, policies or practices.
Barrier-free
Describes a building, space or route that people with disabilities can approach, enter and use without obstacles. It is the term the Ontario Building Code uses, and MLI Select requires barrier-free common areas under CSA B651:23.
Barrier-free path of travel
A continuous route, without steps or other obstacles, that people using wheelchairs and other mobility aids can follow, for example from the entrance to an elevator or washroom. The Ontario Building Code sets its widths, slopes and other features. Try our entrance and route self-check.

C

Captions
Text versions of speech and important sounds, shown in sync with video or live audio. WCAG asks for captions on prerecorded video at Level A and on live video at Level AA.
CART (Communication Access Realtime Translation)
Live, word-for-word captioning typed by a trained human captioner and shown on a screen or device. Government of Canada guidance recommends CART over automatic captions for important events. See our accessible events checklist.
Communication supports
Help that people may need to send, receive and understand information, such as plain language, sign language, captioning, reading aloud or written notes. Under the AODA, organizations provide them on request.
Compliance report (AODA)
A report Ontario organizations with 20 or more employees file to confirm they meet AODA requirements. Businesses and non-profits file every three years; as of October 2026, the next deadline is December 31, 2026. Ontario's reporting requirements.
Contrast ratio
A measure of the difference in brightness between text or graphics and their background, from 1:1 to 21:1. WCAG Level AA asks for at least 4.5:1 for regular text, and 3:1 for large text and for graphics and controls people need to see.
CSA B651
CSA/ASC B651:23, Accessible design for the built environment: the national standard for making buildings and other facilities accessible to people with physical, sensory and cognitive disabilities. Its requirements are minimums, and MLI Select uses it for visitable units, barrier-free common areas and accessible units. CSA B651:23 at CSA Group.
CSA B652
CSA/ASC B652:23, Accessible dwellings: a national standard focused on the accessibility of homes and residential units.

D

Disability
Under the Accessible Canada Act, an impairment or functional limitation, permanent, temporary or episodic, visible or not, that in interaction with a barrier hinders full and equal participation in society. Ontario's Human Rights Code also uses a broad definition that covers past and perceived disabilities. OHRC: What is disability?
Disability justice
A framework, set out in Sins Invalid's 10 principles, that looks at how ableism connects with racism, capitalism and other systems. It centres the leadership of those most affected, interdependence and collective access. 10 Principles of Disability Justice.
Duty to accommodate
The legal duty under Ontario's Human Rights Code for employers, service providers, housing providers and others to accommodate people with disabilities up to the point of undue hardship. It covers both how a request is considered and the accommodation provided. OHRC policy on the duty to accommodate.

H

Human Rights Code (Ontario)
Ontario law that protects people from discrimination because of disability and other grounds in employment, services, goods and facilities, housing, contracts, and membership in trade and vocational associations. The Ontario Human Rights Commission (OHRC) publishes policies on how it applies.

I

IASR (Integrated Accessibility Standards Regulation)
Ontario Regulation 191/11 under the AODA. It sets standards for information and communications, employment, transportation, the design of public spaces and customer service, plus general requirements such as policies, training and accessibility plans.
Inclusive design
Designing products, spaces, services and policies from the start so that people with a wide range of abilities can use them, rather than adding fixes later. The OHRC says inclusive design is preferred over one-off accommodations.
Intervenor
A trained professional who supports communication and access to information for a person who is deafblind, for example by using tactile sign language.

L

LSQ (langue des signes québécoise)
Quebec Sign Language, used by many Deaf people in Quebec and in francophone communities. With ASL, it is one of the two most common sign languages in Canada, and the Accessible Canada Act recognizes both.

M

MLI Select
CMHC mortgage loan insurance for rental projects with five or more units. Projects earn points for affordability, energy efficiency and accessibility, and accessibility is worth 20 points at Level 1 or 30 points at Level 2. MLI Select accessibility points, explained.

O

Ontario Building Code
The regulation that sets construction requirements in Ontario, including barrier-free design. Its accessibility requirements apply to most new construction and extensive renovations, and existing buildings aren't affected unless an extensive renovation is planned. Accessibility in Ontario's Building Code.

P

Plain language
Communication whose wording, structure and design are so clear that the intended audience can easily find, understand and use the information. Canada's national standard is CAN-ASC-3.1:2025. See our accessible documents quick guide.

R

RHFAC (Rick Hansen Foundation Accessibility Certification)
A rating of meaningful access in the built environment, based on the experience of people with disabilities affecting mobility, vision and hearing. A score of 60–79% can earn RHF Accessibility Certified and 80% or more can earn Gold, when prerequisites are met. RHFAC certification: what the scores mean.
RHFAC Professional
A person trained by the Rick Hansen Foundation who has passed a formal exam facilitated by CSA Group, and who carries out RHFAC ratings. RHFAC frequently asked questions.

S

Screen reader
Software that reads aloud what is on a screen, or sends it to a braille display, so people who are blind or have low vision can use computers and phones. It relies on headings, labels and alt text to make sense of content.
Service animal
Under Ontario's customer service rules, an animal that is easily identified as relating to a person's disability, for example by a harness or vest, or one supported by documentation from a regulated health professional. Organizations must welcome service animals unless the law excludes them, and then offer another way to serve the person.
Support person
Someone who goes with a person with a disability to help with communication, mobility, personal care, medical needs or access to goods and services. In Ontario, organizations must welcome support persons and state any admission fee for them in advance.

T

Tactile walking surface indicator (TWSI)
A textured surface that people can detect underfoot or with a cane. Attention indicators, with raised domes, warn of hazards such as stairs and curb ramps; direction indicators, with raised bars, guide people along a route.

U

Undue hardship
The limit of the duty to accommodate. Ontario's Human Rights Code allows only three factors: cost, outside sources of funding, and health and safety. The organization must prove it with objective evidence. OHRC on undue hardship.
Universal design
Designing environments, products and services to be usable by all people, as far as possible, without the need for adaptation or specialized design. MLI Select recognizes universal design units as one way to earn accessibility points. Read Universal design vs accessible design.

V

Visitable unit
A home that offers a basic level of access for visitors, such as people who use a wheeled mobility aid, so they can enter safely, move independently through the visitable level and use the toilet. MLI Select requires every unit to be visitable under CSA B651:23. Preparing for MLI Select accessibility.

W

Wayfinding
The information that helps people find their way, such as signs, maps, landmarks, lighting, colour and tactile or audible cues. Good wayfinding works for people with different senses and different ways of processing information.
WCAG (Web Content Accessibility Guidelines)
The W3C's international guidelines for accessible websites, apps and digital documents, graded at Levels A, AA and AAA. WCAG 2.2 is the current version. Ontario's AODA requires WCAG 2.0 Level AA for public websites of the public sector and organizations with 50 or more employees, with two exceptions. Read WCAG 2.2 in plain language.

Sources

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