The noun axis has 6 senses (first 2 from tagged texts)
1. (6) axis -- (a straight line through a body or figure that satisfies certain conditions)
2. (1) axis, axis of rotation -- (the center around which something rotates)
3. axis -- (the main stem or central part about which plant organs or plant parts such as branches are arranged)
4. Axis -- (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")
5. bloc, axis -- (a group of countries in special alliance)
6. axis, axis vertebra -- (the 2nd cervical vertebra; serves as a pivot for turning the head)