Definitions:
an imaginary line about which a body rotates

a fixed reference line for the measurement of coordinates

a straight central part in a structure to which other parts are connected.

the second cervical vertebra, below the atlas at the top of the backbone.

an agreement or alliance between two or more countries that forms a centre for an eventual larger grouping of nations

a deer that has lyre-shaped antlers and a yellowish-brown coat with white spots, native to india and sri lanka.