Electric is related to Circuit. Circuit is related to Electricity. Electricity is a synonym of Current. Current is related to Pulse. 
Tooth is part of Gear. Gear is a synonym of Great. Gross is etymologically related to Great. 
Electric <--RelatedTo--> Circuit <--RelatedTo--> Electricity <--Synonym--> Current <--RelatedTo--> Pulse 
Tooth --PartOf--> Gear <--Synonym--> Great <--EtymologicallyRelatedTo-- Gross 