Axis
WordNet
noun
(1) The center around which something rotates
(2) The 2nd cervical vertebra; serves as a pivot for turning the head
(3) A straight line through a body or figure that satisfies certain conditions
(4) A group of countries in special alliance
(5) In World War II the alliance of Germany and Italy in 1936 which later included Japan and other nations
"The Axis opposed the Allies in World War II"
(6) The main stem or central part about which plant organs or plant parts such as branches are arranged