Definer - Word Translator, Ask AI, Dictionary Extension

Select text to translate, define, or ask AI. A word translator and dictionary extension for webpages, PDFs, and EPUBs.

Read the articles and books you want in another language, with help close to the text. Definer is a popup dictionary and word translator that brings definitions, contextual translation, pronunciation and AI explanations beside your selection. Get a quick answer, explore an interesting expression or keep something useful for later learning. KEY FEATURES 📖 Dictionary meanings, examples, synonyms and related words 🌍 Translate selected words, phrases and passages in context 🎧 Text to speech, pronunciation recordings and video examples 🤖 AI explanations, writing help and reusable prompts 🔎 Image search, Wikipedia and your own dictionary sources 📚 PDF and EPUB Reader with a personal library 🗂️ Lookup History, editable vocabulary and Anki export 🖱️ Open a lookup beside your text Select text with the mouse, then click the small round Definer icon that appears. You can also use a keyboard shortcut or the Definer command in the right-click menu. Prefer looking up words with a double-click? Enable double-click lookup in the popup settings. 🌍 Understand the sentence and explore the word A translation helps you follow the passage; a dictionary helps you get to know the expression. Translator's In Context section translates the surrounding sentence or paragraph and highlights your selected expression. Compare alternative translations to find the wording that fits the passage. Open the dictionary for meanings, usage examples and related words, then compare those examples with the sentence you are reading. Follow a related term into another lookup when you want to explore further. 📖 Use your preferred dictionaries Add a website dictionary as a Custom source or import a supported Offline Dictionary file. Keep a trusted learner's dictionary or specialist reference alongside the included resources. Choose the language of the answers as well as the language of the text. Keep dictionary explanations in your study language beside a translation into your own language, or choose another result language for a particular resource. 🔎 See what the words refer to When a passage mentions an unfamiliar musical instrument, a translated name may still leave you guessing. Look at pictures from Open Images' openly licensed cultural collections, then open Wikipedia to learn about its history or role. Explore pictures, background information and definitions in the same lookup. 🎧 Connect the written phrase with its sound Listen to a word or selected passage with text to speech. Compare pronunciation recordings from Wiktionary, or use YouGlish to hear the expression in videos. A phrase you recognize on the page may sound quite different in conversation: hearing its stress and rhythm gives you something concrete to listen for next time. 🤖 Reuse the kind of AI help you need Ask why a tense is used, what makes a remark sarcastic or how to make your own sentence more natural. Follow up on the part of the explanation you want to understand better. AI can also summarize selected text or help revise its grammar and tone. Save your usual instructions as prompts: one for grammar at your level, another for a more polite reply. These prompts appear as separate tasks, each with its own conversation for that lookup. Return to the grammar explanation after working on the reply, then reuse either prompt with the next passage. 🗂️ Build editable vocabulary and flashcards Save the information that made an expression useful to you: dictionary meanings and examples, a contextual translation or a helpful AI conversation. Organize it in Collections by book, language or subject, then edit the content in your own words. Recipes let you choose how available results become study material. A custom card can put an example on the front and combine a dictionary meaning with a translation on the back. Once that layout suits your study method, reuse it for later discoveries instead of rearranging each card by hand. 📚 Continue a book in the PDF and EPUB Reader Open course materials, papers and ebooks in Definer's Reader and use your chosen lookup sources inside the document. Books stay in a local library with your reading position, ready for the next session. In an EPUB, move between chapters and adjust the text size. In a PDF, search for a passage, highlight it or add a note. PDF annotations save to the library copy, and you can download an annotated copy to keep or share. 🖥️ Optional Desktop app for Windows and Linux For text in an image, screenshot, app or game, the separate Definer Desktop app adds screen OCR and text recognition. Start Word from its tray menu and click a word, or start Region and drag around a passage. Configured shortcuts offer another way to start. The recognized text opens in Definer's lookup tools, ready for a translation, definition or AI question. ❓ FAQ Can useful phrases be saved after finishing a chapter? Yes. With History recording enabled, reopen recorded lookups in History to revisit their available results and original page context. Choose the expressions worth keeping and save from those results when you are ready. You can finish the chapter before deciding what belongs in your vocabulary collection. How can saved vocabulary be exported? Send flashcards to desktop Anki through AnkiConnect, export Markdown files for notes, choose CSV for a spreadsheet or use JSON for structured data. You can export selected items or whole Collections, so a particular project can travel with the material you chose for it. 🛠️ QUICK HELP If Definer stops responding, restart your browser. If the lookup popup does not appear, check that your chosen activation action is enabled and that Definer is enabled for the current site. You can also click Definer in the browser toolbar, type a word or phrase and press Enter for a manual lookup. For a continuing problem, email definer@lumetrium.com with your browser name, the affected page and a short description of what happened. 📬 CONTACT & COMMUNITY Questions, bug reports or ideas: definer@lumetrium.com Discussion and updates: https://www.reddit.com/r/lumetrium_definer Guides and customization examples: https://lumetrium.com/definer/wiki