This tab shows similar keywords as suggested by Google.

What are similar keywords?
Similar keywords are keywords from related searches that don’t contain the initial keyword phrase. For example, similar keywords for ‘web template’ are ‘web design’, ‘html template’, ‘template monster’, etc.
You can easily discover your key rivals after inspecting the list of similar keywords. For example, the similar keyword list for ‘web template’ contains ‘template monster’ and ‘boxedart’.
Here you will also find common misspellings and typos. For example, the similar keyword list for ‘web template’ contains ‘temlate’, ‘templete’, ‘tamplet’, etc.
Below is the list of the most popular similar keywords for all keywords you selected in the main list. Drag keywords from this list to the main keyword list or to any folder, click ‘Selected’ or ‘All’ button to run commands for all keywords selected in this list, or for all keywords from this list.”

How to discover similar keywords?
Select one or more keywords in your keyword list, then click on ‘Keywords’->’Discover’->’Similar Keywords’->’Google’ menu item. This menu item shows you the number of keywords that have no information about similar keywords. For example, if you select 10 keywords, 3 of which already have information about similar keywords, this menu item will look like ‘Google [7 keywords]’.