PopupWord is a free Chrome add-on designed to enhance vocabulary memorization by prompting users to input a word whenever a new webpage is opened or refreshed. This tool displays a pop-up window requiring the user to enter the corresponding word, reinforcing learning through repetition. Once the correct word is input, the pop-up closes, allowing seamless browsing.

The tool includes keyboard shortcuts for user convenience. Pressing the ESC key can forcibly close the pop-up, while hitting Enter after a correct input will also dismiss the window. Additionally, users can mark words as memorized using the Alt+Enter shortcut, ensuring they will not appear in future prompts. Importantly, PopupWord does not collect any user information, prioritizing user privacy while facilitating effective vocabulary practice.