Primary

a preliminary election where delegates or nominees are chosen

one of the main flight feathers projecting along the outer edge of a bird's wing

(astronomy) a celestial body (especially a star) relative to other objects in orbit around it

coil forming the part of an electrical circuit such that changing current in it induces a current in a neighboring circuit

of first rank or importance or value

not derived from or reducible to something else

most important element

of or being the essential or basic part