---
title: "Plain-English A to Z"
description: "The canonical clinical-to-plain vocabulary, the rule for choosing a replacement word, and the machine-readable list every product and Term instance shares."
url: "https://opsinjs.pensievelabs.org/content/plain-english-a-z"
source: "https://opsinjs.pensievelabs.org/content/plain-english-a-z.md"
section: "Content & language"
kind: "content"
reviewed: "2026-09-20"
reviewer: "content"
aliases: ["clinical vocabulary", "plain words", "clinical terms", "a to z"]
---
> Elements written as `` below are opsinjs documentation
> components. Their attributes are the content: the values they render are
> generated from `tokens/*.json` and `registry/catalogue.ts` and are
> published separately at https://opsinjs.pensievelabs.org/r/index.json and under the Reference
> section.
> Nothing is missing from this page. The data simply does not live in
> the prose.
## The rule [#the-rule]
**This page is canonical for plain language.** Every other page in this system
links here rather than restating a word choice, and `assert-ia.mts` enforces that
they do not restate it. If a clinical term appears in a product built on opsinjs,
its replacement is the one on this page.
The rule for choosing a replacement is four tests, applied in order. A candidate
must pass all four.
1. **Would someone say it out loud?** "Raised" passes. "Elevated" does not. Read
the sentence aloud to somebody who does not work in health; if they would not
use the word in conversation, it is not the replacement.
2. **Does it lose anything the reader needs?** Plain does not mean vague. "Water
pill" is plainer than "diuretic" and it is wrong, because the reader will not
recognise it on the box. When plainness costs accuracy, the answer is both
words, not the plainer one.
3. **Will they meet the clinical term elsewhere?** If the word appears on their
prescription, their letter, their portal or their monitor, they need to
recognise it. Give the clinical term *and* the explanation, in that order,
once, and then use the plain form.
4. **Is it the same word every time?** Synonym variation is a comprehension cost
with no benefit. One clinical term maps to exactly one plain replacement
across the whole product, which is precisely what makes this list worth
having.
### Provenance [#provenance]
Every definition in this list is **written from scratch for opsinjs**. We do not
copy the NHS A to Z or any other Crown-copyright material, and we do not copy
definitions from a dictionary or a manufacturer's leaflet. We cite sources; we
never paste them. If a definition here looks like one you have seen elsewhere,
that is a bug and we would like to know.
This matters beyond licensing. A definition lifted from a clinical source is
usually written for a clinical reader and carries a register the whole list
exists to remove.
### Where the data lives [#where-the-data-lives]
The list is a data file, not prose. It is authored in `tokens/glossary.json`,
emitted into the generated reference, indexed by search, and resolved at runtime
by `Term`. One record per clinical term, and each record carries the clinical
term, the plain replacement, an original one-sentence definition, optional
search synonyms and an optional note about where the reader will meet the
clinical word. The record shape and how to add to it are on
[Glossary](./glossary.mdx).
## Approved / Rejected [#approved--rejected]
Your blood pressure was 148 over 92. Your GP might call the top number "systolic".
Your systolic BP was 148 mmHg and your diastolic was 92 mmHg.
Take this medicine on an empty stomach. That means at least an hour before food.
Administer this medication in a fasted state.
Long-term (lasting months or years)
Chronic
A steroid inhaler (sometimes called a "preventer")
An inhaler
The last pair is the one that catches careful writers out. Deleting the clinical
word made the sentence plainer and made it useless: the reader has two inhalers
in a drawer and needs to know which one this is. Plainness is in service of the
reader's task, not the other way round.
## Patterns [#patterns]
**Introducing a term the reader will meet on a document**
> `Plain phrase`. Your GP might call this `clinical term`.
**Introducing a term the reader has already met**
> `Clinical term` means `plain explanation in one clause`.
**A measurement with a named part**
> Your `measure` was `value`. The `position` number is the `plain name for the
> part`.
**A medicine**
> `Brand or common name` (`what it is for`). Take `dose` `when`.
**A procedure**
> `Plain name`. This means `what physically happens`, and it usually takes
> `duration`.
### The list [#the-list]
The list is short and grows one entry at a time, because every entry is written
rather than imported. An empty or thin list is the honest state of a vocabulary
that is being built properly; see
[Glossary](./glossary.mdx) for how to propose an addition.
## Banned words [#banned-words]
These are banned as *replacements*. They are the plausible-looking plain words
that make things worse.
| Banned replacement | Why | Use instead |
| ------------------------------------- | ----------------------------------------------------------------------------------- | ------------------------------------------------------------------ |
| water pill (for diuretic) | Unrecognisable on the packet. | the medicine's name, plus what it does |
| sugar (for glucose in a result) | Confuses the measurement with the food. | blood sugar, once, then the measure's name |
| bad cholesterol / good cholesterol | A moral frame on a lipid fraction, and readers routinely swap them. | the named fraction, with what a higher figure means |
| tummy | Infantilising, and imprecise across a large area of anatomy. | stomach, or the specific part |
| passed away, lost their battle | Euphemism where clarity is required. | died |
| suffers from, victim of, afflicted by | Frames a condition as an identity or a defeat. | has, lives with. See [Inclusive content](./inclusive-content.mdx). |
| the diabetic, the asthmatic | The condition standing in for the person. | a person with diabetes |
| normal | A verdict about the person. See [Reference ranges](../health/reference-ranges.mdx). | your usual range |
## Related components [#related-components]
* **`Term`** is the inline component that renders a clinical word with its plain
replacement. It resolves against this list; a term not in the list cannot be
rendered, which is deliberate.
* **`Glossary`** is the filterable A to Z above, and the same data.
* **`ResultCard`**, **`AlertBanner`** and **`CareCard`** are bound by this
vocabulary in every string they carry.
* **`DisclaimerNote`** is the one place where a legally-shaped sentence is
permitted, and even there it is written in this register.