主幹

trunk / main / core

owner / master / host / individual or party concerned / God / Lord / main / to indicate or signify / trump card (in card games)

tree trunk / main part of sth / to manage / to work / to do / capable / cadre / to kill (slang) / to fuck (vulgar) / (coll.) pissed off / annoyed

trunk line (of road, network etc) / backbone (cable)

core network

core network / backbone network