Hover any word in YouTube subtitles to get an instant AI-powered definition — in context, with no pausing required. Build your vocabulary while you watch.
The occurrence of fortunate events by chance — finding something good without looking for it.
“The concept of serendipity is fascinating.”
Features
One extension. Zero friction. Learn words in the exact context you heard them.
Simply hover any highlighted subtitle word and an instant definition card appears — no clicking, no tab switching, no interruptions.
Gemini AI understands what the word means in that exact sentence — so definitions are precise, contextual, and actually useful.
Every word you look up is automatically saved to your personal vocabulary dashboard, along with the video timestamp and sentence context.
Export your full vocabulary as Anki flashcards, CSV, or JSON with one click. Study on any device, any time — your words, your way.
How it works
Add Youtube Lexify to Chrome in seconds. Sign up for free — no credit card needed.
Enable subtitles and start watching. Lexify automatically highlights words as they appear.
Hover any word to see an AI-powered definition. The word is instantly saved to your vocabulary.
Pricing
The free tier lets you define 30 words a day. Upgrade to Pro for unlimited lookups and full vocabulary history.