Chrome Extension

Look up any word, without leaving the page.

Select a word anywhere you read and get its definition, CEFR level and pronunciation in a small card — no new tab, no losing your place.

Add to Chrome — it's free

Also works in Edge, Brave, Opera and Vivaldi.

A web article with the word ponder selected; the extension's card is open below it showing the pronunciation, two numbered senses with CEFR levels, and an example sentence. — The card opens where you are reading, and closes with Esc or a click anywhere else.

What's on the card

Up to three senses, numbered, so a word with several meanings stays readable.
A CEFR level on every sense (A1–C2), so you can see at a glance whether a meaning is everyday or advanced.
Pronunciation in IPA, US or UK, with audio where we have it.
An example sentence for each sense.
Two ways of saying it. Every entry is written twice — a precise version for teachers and a plainer one for learners. Switch between them in Settings.

Three ways to look something up

Select and click: Highlight a word and a small icon appears beside it. Click the icon and the card opens in place.
Right-click: Select a word, right-click, and choose "Look up" from the context menu.
Keyboard: Select a word and press Ctrl+Shift+X (Cmd+Shift+X on a Mac). The letter is yours to change in Settings.

Light and dark

The card follows your system by default, or you can pin it to light or dark in Settings. It never appears while you are typing — text boxes, editors and comment fields are left alone.

The lookup card in light mode showing the word bifurcation with three senses.

The lookup card in dark mode showing the word eclipse with three senses.

Questions

Is it free?: Yes, and it stays free. No account, no sign-up, no premium tier, and no advertising inside the extension. It exists to be useful and to introduce people to this dictionary.
What does it send?: Only the word you select, and only when you ask for a lookup. It never reads or sends the address of the page you are on, its title, or anything else on it. Your settings stay in the browser. There is no analytics or tracking of any kind in the extension.
Does it work on PDFs and local files?: On local files, yes, once you switch on "Allow access to file URLs" on the extension's details page in Chrome. Chrome's built-in PDF viewer does not expose selected text to extensions, so PDFs are out of reach.
It is installed but nothing happens when I select a word.: Two things to check. Open chrome://extensions, click Details on English Reference Dictionary, and make sure Site access is set to "On all sites". Then reload the page you were on — content scripts only load when a page loads, so a tab that was already open when you installed will not have it yet.
Why does it ask to read data on all websites?: Because the lookup card has to be able to appear on whatever page you happen to be reading, and there is no way to know in advance which sites those are. The permission covers where the card can appear, not where data goes: the extension only ever talks to englishreference.com, and only to fetch a definition.

The full detail of what the extension sends and stores is in the Privacy Policy. Anything else, or something broken — get in touch.