Look up any word without leaving the page.
Gloss is a free, open-source Chrome extension. Right-click a word or phrase and its definition opens beside it, slang included.
Notes in the margin
A scribe would write a , a short note in the margin, beside any word a reader might trip on. Today that word is as likely to be or as . The fix still holds: the meaning belongs beside the word, not in another tab.
Most of us still do it the slow way. We copy the word, open a new tab, search, skim a few results and come back having lost our place. Do that for every unfamiliar term in a long read and the tab bar fills up long before the article ends.
Glosses solved this a thousand years ago by keeping the explanation within reach of the eye. A good definition should arrive the same way: next to the word, sized to the moment, and gone when you are done with it.
That is the whole idea behind a margin note. It does not ask you to stop reading. It waits beside the line until you need it, answers the one question you had, and lets the page carry on as if nothing happened.
How it works
No new tab. No copy and paste.
Sources
It knows aura farming, clanker and unc.
Gloss asks Wiktionary first. Wiktionary is written by its readers, so this year’s slang sits right next to words like sesquipedalian. When Wiktionary has no entry, Gloss asks the Free Dictionary API instead.
- Noun
The act of cultivating an appearance or aesthetic of effortless, nonchalant charisma.
- Noun
A robot or artificial intelligence.
- Adjective
Old; no longer versed in or relevant to current youth culture.
- Noun
An instance of being uncontrollably angry or upset.
- Noun
Low-quality content produced by generative artificial intelligence, often characterized by hallucinations or a failure to meet the expectations of coherence and relevance.
Definitions from Wiktionary, shared under CC BY-SA 4.0. Click a word to open its full card.
Themes
Seven themes, each in light and dark.
Pick one in Settings. It applies to the toolbar popup and to every card, on every page.
1 of 7
Word bank
Keep the words you look up.
Press Save on a card and the word goes into your word bank, definitions included. Open Gloss from the toolbar to search it, read a word again, or swipe it away.
Try it: press Save on the card at the top of the page and the word lands in this list.
Privacy
The only thing that leaves your browser is the word.
No account, no analytics and no server of its own. Here is every permission Gloss asks Chrome for, and what it does with each one.
- Right-click menu
contextMenus - Adds Define with Gloss to the menu you get when you right-click selected text.
- Storage
storage - Keeps your word bank, your settings and a seven-day cache of definitions on this computer.
- Active tab and scripting
activeTabscripting - Lets the card open in tabs that were already open before you installed Gloss.
- All websites
<all_urls> - Lets the card appear on any page, inside embedded frames too. Gloss reads the text you select and nothing else on the page.
- Two dictionary sites
en.wiktionary.orgapi.dictionaryapi.dev - The only places Gloss sends anything: the word you looked up, with no cookies attached.
Open source
Read every line before you install it.
Plain JavaScript on Manifest V3. No framework and no build step, so what you read on GitHub is exactly what runs in your browser. MIT licensed.
- Download the zip from the latest release and unzip it, or clone the repo.
- Open
chrome://extensionsand switch on Developer mode. - Click Load unpacked and choose the unzipped
Glossfolder.
- 1,521
- lines of JavaScript, in four files
- 0
- dependencies to install, audit or keep updated
- 10
- source files in the whole extension
Questions
Before you install
Does it work offline?
Words you looked up in the last seven days are cached, so they open without a connection. New words need one.
Can I look up phrases?
Yes. Select anything up to 50 characters, like aura farming or crash out. If neither Wiktionary nor the Free Dictionary has an entry, the card tells you.
Do saved words sync between computers?
No. They stay in Chrome’s local storage on the computer where you saved them, and removing Gloss deletes them.
Can I define a word with a double-click?
Yes. Click the Gloss icon in the toolbar, open Settings and turn on Double-click to define. It starts off, so selecting text to read along works as usual until you want it.