Definitions
Search popularity
Collects what people searched before and after this term, weighs those related terms by their search index, and ranks them from most to least popular.
Search change
Related terms collected the same way, ranked by how much they changed from the previous week (up or down). ↑ means more than last week, ↓ means less.
Relevance
How many people who searched this term also searched the related one; the closer to 100%, the more related.