the central part of a car wheel (or fan or propeller etc) through which the shaft or axle passes
車のホイール（またはファンやプロペラなど）の中心部で、ここをシャフトまたは心棒が通っている
hub
a center of activity or interest or commerce or transportation; a focal point around which events revolve; "the playground is the hub of parental supervision"; "the airport is the economic hub of the area"
(Sound)
