With a javascript-enabled browser, put the cursor over the word and see the definition at the bottom of your window. Or, click the word for the definition at the bottom of page.
It is useful to open two windows at the same time.
Keeping the lesson window on one side of the screen and the other site on the other side of the screen.
Then you can easily jump back and forth between the two windows.
With Windows, right-click the link, then choose New Window with this Link.
With Macintosh, click the link and hold down the mouse button, then choose New Window with this Link.
Vocabulary
javascript-enabled browser
Any browser that supports javascript and has javascript enabled. Netscape Navigator 2.0 or newer and Microsoft Internet Explorer 3.0 browsers support javascript.