Siphon 吸词 is a free Chrome browser add-on developed by Four Feet Studio. The program aims to facilitate vocabulary accumulation through English reading in a simple and enjoyable manner. With Siphon, users can quickly record unfamiliar words encountered while reading online, along with their definitions. Additionally, the tool emphasizes capturing word usage by automatically saving the sentences in which the words appear, along with their source URLs.

Furthermore, Siphon offers a card-like review system for efficient vocabulary revision, providing a visually appealing and interactive experience akin to playing cards. Users can practice spelling words through typing exercises, complete with sound and visual feedback, making the learning process engaging and effective. The add-on also tracks users' vocabulary learning progress, showcasing their word accumulation journey and daily review statistics.