Expansion is related to Extend. Extend is a synonym of Cover. Discourse is a type of Cover. 
Trap is a type of Device. Trap is related to Web. Web is related to Site. Region is a type of Site. 
Expansion <--RelatedTo--> Extend <--Synonym--> Cover <--IsA-- Discourse 
Device <--IsA-- Trap <--RelatedTo--> Web <--RelatedTo--> Site <--IsA-- Region 