hub 
/ˈhʌb/ noun
plural hubs /ˈhʌb/ noun [count] 1 : the central and most active part or place
▪ the hub of the city ▪ The island is a major tourist hub. [=a place where many tourists go] ▪ She was at the hub of all the activity. 2 : the airport or the city through which an airline sends most of its flights
▪ All of the airline's coast-to-coast flights pass through its hub. 3 : the center of a wheel, propeller, fan, etc.
▪ The spokes attach to the hub of the wheel.
▪ the hub of the city ▪ The island is a major tourist hub. [=a place where many tourists go] ▪ She was at the hub of all the activity.
▪ All of the airline's coast-to-coast flights pass through its hub.
▪ The spokes attach to the hub of the wheel.
