QuickDef, an AI-powered dictionary extension, launches to help English learners understand words in PDFs and web pages by double-clicking

QuickDef is an AI dictionary designed for English learners that works inside PDFs and on web pages—addressing a gap where most dictionary extensions fail in PDFs.

Users double-click any word to see AI-generated, learner-friendly definitions with context-aware meaning selection, presented in a clean popup without interrupting reading flow. The extension also allows saving words for later review.

QuickDef processes only the selected word and limited surrounding context when generating explanations, and is free to start with no setup required. Version 1.1.2 was updated April 22, 2026.