secondary

(ornithology) Any flight feather attached to the ulna (forearm) of a bird.

(aviation) A radar return generated by the response of an aircraft's transponder to an interrogation signal broadcast by a radar installation, containing additional encoded identification and situational data not available from a simple primary return.

(military) The second stage of a multistage thermonuclear weapon, which generates a fusion explosion when imploded as an indirect result of the fission explosion of the primary, and which, in a few extremely large weapons, itself implodes a fusion tertiary.

(finance) An act of issuing more stock by an already publicly traded corporation.

(American football, Canadian football) The defensive backs.

(electronics) An inductive coil or loop that is magnetically powered by a primary in a transformer or similar.

One who occupies a subordinate or auxiliary place; a delegate deputy.

(astronomy) A secondary circle.

(astronomy) A satellite.

(education) A secondary school.

Anything secondary or of lesser importance.