Comprehensive Contextual Dictionary
Bidirectional search in 12 languages, contextual meaning analysis based on the sentence, collocations, and audio pronunciation.
Free browser extension for Chrome, Edge and Firefox
Secure your vocabulary for good!
Learn English Words Permanently in Context with Its Built-In, Comprehensive Modern Dictionary!
With a single click, save the unfamiliar words and phrases you are interested in learning while reading, review them, and make them a natural part of your everyday speech.
- Save the words and expressions you want to remember with one click
- Review them regularly so you can use them naturally in conversation
- Instant synchronization across web app, mobile app, and browser extension
Standout Tools
Personal Word & Phrase Notebook
Add multiple tags (Add Tag / Manage Tags), personal notes (Add Note), and AI-powered memory associations (Generate Mnemonic) directly from the extension.
Dejavu Effect™
When your saved words appear in new texts you read in Dejavu Reader, they are automatically highlighted in colors reflecting their memory stage — reinforcing them across different sentences.
Spaced Repetition & Full Sync
Every word and phrase you add via the web app, mobile app, or browser extension syncs instantly in your central digital notebook.
Save what you want to learn. Remember it later.
Save useful words and expressions while you browse, then review them at the right intervals. The extension works fully synchronized with the Dejavu English web app, so the English you meet can become part of your long-term memory.
Words
A word you care about? Double-click it
On any website, double-click a word. You get a proper dictionary entry: meaning in your language, English definition, CEFR level, how common it is, pronunciation, examples, collocations and synonyms. One click sends it to your word notebook, where you can add tags, personal notes, and AI mnemonics directly from the extension.
- No copy and paste, and you stay on the page
- Add tags, personal notes, and AI-powered mnemonics right inside the extension
- Turn double-click off any time if you prefer typing or right-click
Context
Select a sentence to learn a word in context
Select a sentence and right-click. The extension shows the root and base form of the word you are looking up, so inflected forms do not get in the way. You learn what the word means in that sentence and how it is used in context. The sentence is saved with the word in your notebook.
- Works with a sentence you select or one you type yourself
- Context is what makes a word usable later
Phrases
The phrases that make you sound fluent
Fluency is rarely a pile of single words. Select an expression, translate it naturally, and save it to your phrase notebook. Dejavu will remind you to practise it with spaced repetition — that is how eloquence is built, from English you actually met.
- Listen to the phrase
- See similar phrases already in your notebook
Reader
Send any article you are reading to Dejavu Reader in one click
Open the extension’s “This Page” tab on any English article and send it directly to Dejavu Reader. The page is cleaned up from distractions so you can read comfortably and save the article to continue whenever you like.
- Quick Save keeps the article in your reading list without opening it
- Analyse & Preview opens the clean article view in Dejavu Reader immediately
Dejavu Effect™
Your saved words light up by memory stage in every new text
With the Dejavu Effect™, whenever words from your vocabulary notebook appear in a new article you read in Dejavu Reader, they are automatically highlighted in colors reflecting their memory status (Sensory, Short-term, Long-term). Unfamiliar words are underlined so you can click any word for instant contextual dictionary lookup.
- Reinforce saved words naturally by encountering them across different real sentences
- Color-coded legend for Sensory (pink), Short-term (yellow), and Long-term (green) memory stages
- Click any underlined word in the text for instant contextual meaning and one-click saving
Vocabulary Hunter
How much of the article do you understand right now?
Switch to the Vocabulary Hunter tab to get a complete breakdown of the article’s vocabulary against your personal notebook. See the exact percentage of your notebook words found in the text, explore new candidate words to learn, and inspect how your saved words are used in the article’s sentences.
- Category A lists words in the article that are not yet in your vocabulary notebook
- Category B lists words from your notebook found in the text, along with occurrence counts and exact sentences
- See the percentage of your vocabulary notebook words that appear in the article at a glance
Install from the official stores
Chrome Web Store
For Chrome, Microsoft Edge, Brave and other Chromium browsers. Installed from the official Chrome Web Store listing.
Open Chrome Web Store
Firefox Add-ons
For Mozilla Firefox. Installed from the official Mozilla Add-ons listing, reviewed by Mozilla.
Open Firefox Add-onsGetting started takes a minute
- Install the extension from the Chrome Web Store or Firefox Add-ons.
- Sign in once with your Dejavu English account — it stays signed in.
- On any English page, save a phrase that sounds right or look up a word you care about.
- Dejavu tracks the reviews and reminds you with spaced repetition until they stick.
What the extension can see
A dictionary that works on every page needs permission to read pages. Here is exactly what that means:
- The word or sentence you double-click or select is sent to Dejavu English to be looked up. Nothing else on the page is read.
- Article text leaves your browser only when you press Analyse & Preview or Quick Save yourself.
- Your sign-in is kept as a token on your own device, per browser. No password is stored in the extension.
- There are no ads and no third-party trackers inside the extension.
Frequently asked questions
Is the extension free?
Yes. The extension is free and works with a free Dejavu English account. Some advanced study features on the website belong to the Pro plan, but looking words up, saving them and reading pages do not.
Why should I use Dejavu English instead of Anki?
In Anki, you have to build flashcards manually one by one, and words remain disconnected from the texts you read. In Dejavu English, you save a word with a single click while reading; its built-in dictionary automatically fetches its real meaning in that sentence, CEFR level, usage frequency, pronunciation, and examples.
Which browsers does it support?
Chrome, Microsoft Edge, Brave and other Chromium-based browsers through the Chrome Web Store, and Mozilla Firefox through Firefox Add-ons. Install it once per browser; each browser keeps its own sign-in.
Do I have to leave the page to look a word up?
No. Double-clicking a word opens the dictionary over the page. Selecting a sentence and using the right-click menu works the same way.
Can I turn double-click lookup off?
Yes. There is a switch at the bottom of the extension’s Dictionary tab. Turn it off and words are only looked up when you type them or use the right-click menu.
What happens to the words and phrases I save?
They go to your central digital notebooks with the sentence you met them in, synced across web, mobile, and extension. Dejavu tracks how often you need to see them and brings them back with spaced repetition, flashcards, and the Dejavu Effect™ in new texts until they stick.
If this is what you have been looking for, start here
Install the extension, sign in once. Save the English you meet. Dejavu will remind you until it is yours.