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Jargon and unusual words with no definition
A car rental booking offers cover for the excess, an insurance word that looks like an everyday one, and nowhere on the page says what it means.
<p>Excess: 1,000.00 …</p> The problem
People who don't know the insurance meaning of excess can't tell what the 1,000.00 is
A car rental site's booking has an Extras step. Under the heading Protection, it says "Excess: 1,000.00 for each accident", and offers a checkbox: "Excess cover, 12.00 a day". To anyone who works with insurance, that is a complete offer. If the car is damaged, the hirer pays up to 1,000.00 towards the repair for each accident and the insurance pays the rest, and excess cover brings what they pay down to nothing.
To someone hiring a car for the first time, excess is an everyday word for too much of something. They may take the 1,000.00 for a deposit held on their card, or for the most the insurance will pay out, and excess cover for an extra fee they can skip. Nothing on the page, or anywhere on the site, says which. They decide on 12.00 a day without knowing that it settles whether one scrape costs them nothing or 1,000.00.
Success criterion 3.1.3, Unusual Words, is Level AAA. It asks for a mechanism to find the specific definition of words or phrases used in an unusual or restricted way, including idioms and jargon. WCAG defines jargon as words used in a particular way by people in a particular field, and excess is exactly that: in insurance it is the part of each claim the customer pays, a meaning the everyday word doesn't give. Its Understanding document lets authors count on readers using context, and on a specialist audience knowing its own words, but it encourages meeting the criterion for specialised information written for non-specialists, which is what a booking page for the public is.
The page gives no definition: not in the sentence, not under it, not behind a link, not in a glossary that can be found from the site. A paragraph carries only the words the author wrote, so there is no meaning for a browser, a screen reader or a reading tool to pass on either. The reader has the word, the number and a checkbox, and has to bring the insurance meaning with them.
The word sits on the line that decides what an accident will cost, so a wrong guess costs money, not only a moment's doubt: someone who takes the 1,000.00 for a refundable deposit, or excess cover for an optional fee, turns the cover down for the wrong reason. The same happens with any trade word in a sign-up or checkout flow, such as "prorated" on a plan change, "pre-authorisation" on a card payment or "sum insured" on a policy.
2 of 10 groups affected
- No vision (not affected)
- Low vision (affected)
- Colour vision (not affected)
- No hearing (not affected)
- Hard of hearing (not affected)
- No speech (not affected)
- Motor (not affected)
- Reach, strength (not affected)
- Cognitive (affected)
- Seizures (not affected)
- Limited language, cognitive and learning abilities People with language or learning disabilities, and people with memory loss, often know only the everyday meaning of a word. They read excess as too much of something, take the 1,000.00 for a deposit or a fee, and choose on that, with nothing on the page to correct them.
- Limited vision People who zoom in see a few words at a time, so they lose the surrounding text that might have hinted at what the word means, and a definition anywhere but beside the word is out of view.
Nothing in the markup is wrong, so no automated check finds it: axe and the other rule sets used for audits have no rule for 3.1.3, and EaseWeb's audit has no check for it. Whether a word is used in a narrow sense depends on the field, the audience and the sentence, and code can't tell that. An AI assistant asked to review the page sees a paragraph and a labelled checkbox. Asked about the wording, it may well know what an excess is and see nothing missing, which is the blind spot of every expert reader, the writer included. Readability scores don't find it either: "Excess: 1,000.00 for each accident" is a short line of common words.
Try it
Work out what the 1,000.00 excess is, using only what the page says
This is the extras step of a car rental booking. Choose an answer under it, then apply each fix, find where the page says what the excess is, and answer again.
Broken Can you fix this?
Protection
Excess: 1,000.00 for each accident
What is the 1,000.00?
The fix
Say what each trade word means, where people read it
<h2>Protection</h2><p> Excess: 1,000.00 for each accident</p><label> <input type="checkbox" name="excess-cover"> Excess cover, 12.00 a day</label>What is wrong2 points
- In insurance, excess means the most the hirer pays towards damage in each accident, a meaning the everyday word doesn't give.
- Nothing on the page, or on the site, says what it means, and the offer of excess cover depends on it.
Define the term where it is used
<h2>Protection</h2><p> Excess: 1,000.00 for each accident. This is the most you pay towards damage to the car; the insurance pays the rest.</p><label> <input type="checkbox" name="excess-cover"> Excess cover, 12.00 a day: you pay nothing towards damage</label>How it is fixed2 steps
- Write the meaning straight after the term, in the same paragraph and in everyday words: the most you pay towards damage to the car, with the insurance paying the rest. This is W3C technique G112, an inline definition.
- Say in the checkbox's label what excess cover does for the reader: they pay nothing towards damage. The label is the checkbox's name, so a screen reader reads the meaning with it.
This fixes the Before and passes 3.1.3. Every reader meets the meaning together with the word, without having to know that there is anything to look up, and it reaches every browser, screen reader and translation tool as part of the text. It costs one sentence on the page.
Why this fix: Explain a word where it is used
All three pass. Define the term in the sentence: it is the one way that reaches readers who don't know the word is a term at all, and it costs one sentence and no code. Use the disclosure when the definition is long, or when a page has many such words and printing every definition would bury what people came to do. Link to a glossary when the same terms appear on many pages, or when the full meaning needs examples and exceptions; where a decision on the page depends on the word, give the short meaning in the sentence as well.
Finding the words is the work. Read the page as the least experienced customer it serves, and look for three kinds: words of a trade (excess, prorated, pre-authorisation), everyday words given a narrow meaning in this field, and words the company made up, such as the name of a plan or a feature. The Understanding document says plainly that new and invented words are not exempt.
Idioms are the other form the failure takes: "a ballpark figure", "out of pocket", "we'll circle back". Where you can, rewrite them in literal words, so there is nothing left to define. Where a phrase has to stay, such as in a slogan, the same three fixes apply.
Write a definition in words simpler than the term: "the most you pay towards damage", not "the deductible amount", which is another term. Say what it means for the reader in this case, with the page's own number where there is one. Then use the same word for the same thing everywhere: a site that says excess on the booking and deductible in the confirmation email has two words to define, and readers will take them for two things.
Don't put the definition only in a title attribute or in a tooltip that opens on hover. It shows only to a mouse resting on the word, never on a touch screen or to a keyboard; see form field labels and hints only in a title tooltip, which fails the same way. A dfn element around the term (technique H54) marks the place where it is defined, but it is not a definition: the meaning still has to be written beside it.
An abbreviation such as CDW, a collision damage waiver, is a different failure: see abbreviations and acronyms that are never spelled out. When the whole text is hard, not one word, as in a long rental agreement, see terms and policies with no plain-language summary.
Design ideas
A meaning can be shown in more than one way
Three more ways to give the meaning of excess, and one that only looks as if it does. Point at them, tap them and Tab to them.
In the design file
- Mark every trade word on the page, and write its meaning in the words a first-time customer uses.
- Put the meaning on the same screen as the word, on a phone too.
- Draw any button that opens a meaning both closed and open, and with its focus ring.
- Use one word for one thing on every page, and in the emails and the contract too.
Passes
The most you pay for damage (excess): 1,000.00
Plain words first, the term in brackets The line leads with what the reader needs, and keeps the trade word in quieter grey after it, 6.04:1, for when they meet it again in the contract.Rule of thumb: Explain a word where it is used
Excess: 1,000.00
The most you pay towards damage to the car in each accident. The insurance pays the rest.
Info button with a bubble A small round “i” after the word opens the meaning in a bubble on a click, a tap, Enter or Space, and the bubble stays until the button is pressed again. Hover alone never opens it, so a phone gets the same as a mouse.Excess: 1,000.00
Words in this step
- Excess
- : the most you pay towards damage.
- Excess cover
- : you pay nothing, for 12.00 a day.
A card of the words in this step One soft card beside the options defines each word the step uses, once, so the line itself stays short. It suits a step with several such words; keep it on the same screen as the choice.
Fails
ExcessThe most you pay towards damage to the car in each accident. The insurance pays the rest.: 1,000.00
Dotted underline with a hover tooltipWCAG 3.1.3 The dotted line promises a meaning, but only a mouse resting on the word opens it: a keyboard never reaches the word, and a touch screen never shows the tooltip. A title attribute fails the same way.See also: Form field labels and hints only in a title tooltip
Verify the fix
4 checks, no mouse.
Test with: Keyboard, Touch, Screen reader
Record the OS, browser and assistive-technology versions, the build, the date, and the actual result of each step. Repeat whenever the copy changes.
Limits
This is a starting pattern, not a guarantee. The example is one word on one booking step. 3.1.3 is Level AAA, above the AA level that most policies ask for, but a definition costs a sentence, and on a booking or checkout page it decides whether people know what they are paying for. Which words need defining depends on who reads the page, so a page for specialists can define fewer than a page for the public. Definitions don't make a hard text easy: they help with single words, and a page full of them needs rewriting more than it needs a glossary.
This is a recreated teaching example, not a finding about a named client. The code is a starting pattern: test it in your own product. No completed assistive-technology test is claimed here.
References
- WCAG Understanding: unusual-words (opens in a new tab)
- WCAG Technique G101 (opens in a new tab)
- WCAG Technique G112 (opens in a new tab)
- WCAG Technique G55 (opens in a new tab)
- WCAG Technique G62 (opens in a new tab)
- WCAG Technique H40 (opens in a new tab)
- w3.org: coga-usable (opens in a new tab)
- w3.org: coga-usable (opens in a new tab)
- developer.mozilla.org: details (opens in a new tab)
- html.spec.whatwg.org: dom (opens in a new tab)
EaseWeb service
Fixed it? Keep it from coming back.
I turn guides like this one into rules your coding agents follow and checks your CI runs. Then I retest by hand with a keyboard and screen readers, periodically.