幕境 is a free utility tool designed for Windows, aimed at enhancing English language learning through context-based vocabulary acquisition. By generating thesauruses from MKV video files, users can create a personalized word bank where each term is tied to specific contexts found in movies, series, or documents. This approach facilitates immersive learning, allowing users to engage more deeply with the material they enjoy while expanding their vocabulary.

The program allows for the memorization of words, sentences, and subtitles, making the learning process interactive. Users can practice spelling and watch relevant video clips to reinforce their understanding. Additionally, the integration with Dammu enables users to review thesaurus entries while watching their selected content, making vocabulary retention more efficient and enjoyable.