Meaning of Agena

A•ge•na

Pronunciation: (u-jē'nu), [key]
— n. Rocketry.
  1. a U.S. upper stage, with a restartable liquid-propellant engine, used with various booster stages to launch satellites into orbit around the earth and send probes to the moon and planets: also used as a docking target in the Gemini program.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.