One of my students hovered over a word in a Word document, for a few seconds,
and the definition of the word popped up like a Screen Tip. We can't make it
happen again. Any one know how this works?
There's nothing in the standard Word features to do that. It can be
deliberately created by turning the word into a hyperlink and putting
the definition into the hyperlink's tooltip. The usual
blue-and-underline formatting can be removed to make it not look like
a hyperlink. The giveaway is that the tooltip always has "Click to
follow link" at the bottom.
The built-in feature to get definitions works by holding the Alt key
while clicking on the word. That opens the Research pane on the right,
with definitions and, optionally, translation to other languages.
