Toggles word-highlighting for the word under the cursor in all source windows. This is like using a highlighter pen on paper. If you select a word, and use the Highlight Word command, then anywhere that word appears in your source, it will appear highlighted.
By default, the highlight appears like bold black text with a bright yellow background. However, you can set the highlight effect yourself by editing the Highlight style. The Style Properties command is used to edit styles.