Weblio エクステンション is an official extension provided by GRASグループ株式会社. This Chrome add-on allows users to easily access word definitions and explanations by simply selecting a keyword. Once a keyword is selected, a pop-up window will appear with the corresponding explanation. Users can also click on links within the window to directly navigate to the detailed explanation page on Weblio's website.

With Weblio エクステンション, users can benefit from the following features:

• Instant access to word explanations within a pop-up window.
• Quick navigation to Weblio's explanation page by clicking on links within the window.

To use the extension, users need to select the word they want to look up and press the Ctrl key. The pop-up window will display the explanation. Clicking on "続きを読む" will redirect users to Weblio's page for more detailed information. Pressing Ctrl key again while the window is open will close it.

Users can customize the shortcut key for searching and access the options menu by clicking on the blue "W" icon in the top right corner. From the options menu, users can also perform searches directly in the Weblio dictionary, which will open the search results in a new tab.

Overall, Weblio エクステンション is a convenient tool for users who frequently need to look up word definitions and explanations. It provides a seamless browsing experience and eliminates the need to navigate away from the current page.