Secondary is the opposite of Main. Main is related to Town. Town is related to Local. 
Address is related to Link. Link is related to Missing. Missing is similar to Lost. Lost is related to Forget. 
Secondary <--Antonym--> Main <--RelatedTo--> Town <--RelatedTo--> Local 
Address <--RelatedTo--> Link <--RelatedTo--> Missing <--SimilarTo--> Lost <--RelatedTo--> Forget 