(Greek mythology) A giant-hunter, pursuer of the Pleiades and lover of Eos, and killed by Artemis.

plural of Orion

(astronomy) A diffuse nebula visible in the night sky below Orion's Belt; it is approximately 40 light years across. It is one of the brightest nebulae visible to the naked eye and is the closest region of stellar formation to Earth.

(astronomy) A bright asterism located near the celestial equator; it consists of three bright stars lined up and visibly close together. It is part of the constellation Orion and includes the stars Alnitak (ζ Ori), Alnilam (ε Ori), and Mintaka (δ Ori).

(astronomy) A minor spiral arm of the Milky Way galaxy, containing the Solar System.

An asterism in the constellation Orion, consisting of the three bright stars Alnitak, Alnilam and Mintaka.

(astronautics, science fiction) A theoretical means to propel spacecraft through space, by detonating nuclear bombs behind the spaceship and riding the nuclear explosions that push against the rear mounted pusher plate.

plural of Orion drive

plural of Orionid

Any of the meteors in a prolific meteor shower associated with Halley's Comet.