What is accessibility and why does it matter? Part 0 of a series introducing accessibility, assistive devices and technology, inclusive design, and web accessibility standards and tools. Will include asides on why language matters, the medical vs social models of disability, why Comic Sans isn't the worst thing ever, and fun with acronyms - WCAG, POUR, ARIA and more! Glossary will be updated as the series develops.
A numeronym for the word "accessibility". The number 11 indicates the characters between the first and last characters in the word being shortened. In this case, accessibility is 13 letters long, so we get a11y instead. A real finger saver - I can never get all the 's's and 'i's in the right order!
As you may have guessed from the "ism" ending, this term is used to describe discrimination and prejudice against people with disabilities.
Ableism is the more common term in North America, but people in the UK tend to use disablism instead.
If you just search for "accessibility", you're likely to get the Wikipedia accessibility article, which defines accessibility as: "the design of products, devices, services, or environments for people who experience disabilities."
However, if you use Google's define feature (type "define: accessibility" into the Search bar), you'll get these interlocking definitions, which I prefer:
- the quality of being able to be reached or entered
- the quality of being easy to attain or use
- the quality of being easily understood or appreciated
A subset of assistive technology focusing on items specifically developed for people with disabilities. Cochlear implants are an example of adaptive tech, since they were specifically developed for those with hearing loss or d/Deafness.
The opposite of autistic. When speaking about the differences between an autistic and someone who is not autistic, it is helpful to have a mirror term, rather than using incorrect and potentially offensive language like "normal" and "you know, a regular person". 
An umbrella term for any disorder that affects the joints of the body, although other organs can also be affected by arthritis. Primary symptoms are joint pain, loss of range of motion, stiffness, and swelling. Common sub-types are rheumatoid and osteoarthritis.
Anything that helps someone do something they wouldn't otherwise be able to do. For instance, a cane is an assistive device to someone with mobility issues, while a screen reader is assistive technology for someone with vision loss, or who is blind.
More specifically, Wikipedia considers AT to be a blanket term for rehabilitative, adaptive and assistive technologies, which all have specific definitions and uses.
Someone who assists a PwD in their day-to-day tasks, including things like managing medications, assisting with personal hygiene such as bathing and hair washing, and cooking meals. One of the primary concerns of a caregiver should be respect for and the dignity of the person they are helping.
The symbolic meaning of word or term, often carrying cultural and/or emotional context. For example, the International Symbol of Access (blue and white person in a wheelchair) has a connotative meaning of the removal of barriers to access, use and inclusion. Contrasts with denotation.
A numerical representation of how distinct the colour of the text is against the colour of the background. A standard minimum ratio of 4.5:1 is required for text to be considered sufficiently legible by most users.
The easiest way to understand why this is important is to give it a try: the Contrast Ratio tool by Lea Verou is one I use often. Compare the ratio and legibility of black text on a white background, light grey text on a white background and, just for kicks, Iron Man red (background) and gold (text).
Two facets of deafness are indicated by the doubled "d" and differing capitalization. This article on "Big D" and "Small d" in the Deaf Community explains it better than I can, but to summarize: the large/capitalized D indicates ties to Deaf culture and people who have a strong Deaf identity. The small d indicates those not associated with Deaf culture, and/or those with hearing loss (vs total deafness).
The literal meaning of a word or term; generally what is found in the dictionary. For example, the dictionary definition of wheelchair is "a chair fitted with wheels for use as a means of transport by a person who is unable to walk as a result of illness, injury, or disability." Contrasts with connotation.
Turning again to Wikipedia, we have this definition from the Disability article:
an impairment that may be cognitive, developmental, intellectual, mental, physical, sensory, or some combination of these. It substantially affects a person's life activities and may be present from birth or occur during a person's lifetime.
It's a good starting point, but as I explore the medical and social models of disability in a future article, you'll see why this definition from the World Health Organization is more accurate:
Disabilities is an umbrella term, covering impairments, activity limitations, and participation restrictions. An impairment is a problem in body function or structure; an activity limitation is a difficulty encountered by an individual in executing a task or action; while a participation restriction is a problem experienced by an individual in involvement in life situations. Disability is thus not just a health problem. It is a complex phenomenon, reflecting the interaction between features of a person’s body and features of the society in which he or she lives.
The fundamental aspect of disability etiquette is "Do Not Assume". Don't assume that someone in a wheelchair needs (or wants) help. Don't assume that a person traveling with a carer is non-verbal and/or incapable of understanding you. Don't assume someone with an invisible disability is faking when they use an accessible parking spot. Don't assume that someone without an obvious disability is not disabled.
A chronic pain condition which also includes symptoms of extreme tiredness, sleep difficulties and memory issues. Affecting women twice as often as men, it is still a controversial diagnosis in some medical communities due to the lack of physical abnormalities and objective diagnostic tests.
Any disability that doesn't have obvious indicators (such as a cleft palette, or working with a guide dog). Over 95% of people with chronic medical conditions have no outward signs or markers, and 10% of those are considered disabled. In particular, types of mental illness make up a large portion of invisible disabilities, causing few to no physical signs or symptoms.
Terms that emphasize that the disability or condition is an essential part of the person, not something that can be separated out. Popular in the autistic community, use autisic or autisic person instead of person with autism.
An evolution of accessibility, inclusive design has been defined as:
design of mainstream products and/or services that are accessible to, and usable by, as many people as reasonably possible ... without the need for special adaptation or (specialized) design.
This article on Forbes, Inclusive Design: Making The Web Accessible For All goes into more detail, but I like to define inclusive design by example.
If the developers and designers of a website or application ensure that all text and backgrounds follow minimum contrast ratio guidelines, they have not only made their site/app accessible for users with low vision, they've also made it possible for someone using their phone in bright sunlight to read the content as well.
A system for looking at disability from a medical perspective, where disabilities are defects that must be fixed. This model centers the disability rather than the person, and leads to trying to fit everyone into a box of "normal" behaviours and functionality. The medical model can be useful for temporary disabilities such as a broken arm, which can and should be addressed medically.
Someone with a neurological disorder, such as autism, ADHD, anxiety or congenital mental disability. The opposite of neurodiverse is neurotypical. 
A person without any type neurological disorder. Originally used as a label for non-autistics, it has been replaced by allistic, and broadened in scope. The opposite of neurotypical is neurodivergent. 
Device carried by those with respiratory or heart conditions, to ensure they are properly oxygenated and able to breathe freely.
Any disability that will not be resolved with time and/or treatment. Permanent disabilities can be managed, but not cured. For example, traumatic brain injury can be permanently disabling.
A melding of person-first and identity-first language that centers each individual's preferences. When talking about Gabriel you should use the term dwarf (identity-first), but Aleksander prefers person with cystic fibrosis (person-first).
Used to avoid dehumanization by centering the person, not the condition. Use people with disabilities instead of disabled people.
An abbreviation for "people with disabilities". To be explored fully in another article, but person-first language is very important in many disability communities (and not used or desired at all in others!)
Anything used to help recover functionality and ability after an injury or illness. Rehabilitative technology is generally used in the short term, leading either to the restoration of function/ability, or to more permanent assistive or adaptive tech.
A system for looking at disability from the perspective that it's not people's bodies that are the problem, but rather how society is unwilling to accommodate these differences. For a person who is deaf, a video without captions is the problem that needs a solution, not their deafness.
An abbreviation for "temporarily able-bodied". A hotly contested term in disability communities, it was introduced to try to build empathy and understanding by reminding non-disabled people that they're only one accident or illness away from a disability. You may also see AB, for able-bodied.
Any injury or illness that can be resolved with time and/or treatment. For instance, in most cases a concussion will be fully healed within three weeks and the only necessary treatment is rest and monitoring.
Any disability that has an obvious indicator, such as a person with Down Syndrome. These visual indicators of disability can cause confusion in non-disabled people due to common assumptions of what disability actually is. For example, when a person using a wheelchair stands up to grab something from a high shelf, some observers will assume they are faking or lazy, rather than understanding that disabilities vary from person to person, as well as day-to-day.
 Autistic, Allistic, Neurodiverse, and Neurotypical: Say What? by Svannah Logsdon-Breakstone is a great primer on these terms and how they interact with each other.
Please let me know if there are any terms you'd like to see added to this list!