a straight line through a body or figure that satisfies certain conditionsthe center around which something rotates
同义词：axis of rotation
the main stem or central part about which plant organs or plant parts such as branches are arrangedin World War II the alliance of Germany and Italy in 1936 which later included Japan and other nationsa group of countries in special alliance
同义词：bloc
the 2nd cervical vertebra; serves as a pivot for turning the head