What are Preposition Keywords?
Edited
Preposition keywords are often used by people who are researching products or have an intention to make a purchase.
For example, when people want to buy something, they might search for terms such as "shoes for kids" or "dresses under 100".
Hence, to help you find keywords that signal high intent, we append words such as:
for
about
under
above
and more...
...after your seed keyword to help you find useful keyword suggestions.
You can get the list of preposition keywords by making a search on Keyword Tool and switching to the Prepositions Tab.