轂

The central block (typically dense hardwood) serving as the interface between the axle (軸) and the spokes (輻). In philosophical or political contexts, it may be used metaphorically to denote a central pivot, an indispensable core, or a central authority around which other elements revolve.

The term is defined by its relationship to other components of chariot technology: 軸 (axle), 輻 (spokes), and 輪 (the wheel as a whole).

U+8EF2 and the simplified form (毂) are graphical variants with no change in meaning.

Depending on context, the translator should distinguish between the hub's mechanical function as a point of rotation/pivot and its structural role as the anchor for the spokes (particularly in descriptions of vehicle failure, where the hub may split or loosen).