plural of galactic halo

plural of active galactic nucleus

(astronomy) A compact region at the center of a galaxy that has a much higher than normal luminosity over at least some portion, and possibly all, of the electromagnetic spectrum.

(humorous) A notional space monster invoked to explain the high failure rate of probes sent to Mars.

(astrobiology, astronomy) the zone in a disk galaxy lying within the disk which is neither too far from the core so as to be lacking in heavier elements, nor too close to the core as to experience excessive exposures to supernovae, where intelligent life may develop

plural of galactic habitable zone

(soccer) A football superstar.

plural of galactico

Misspelling of galactitol.

(science fiction) A compendium of all knowledge, or most of the important knowledge, an encyclopedia for a galaxy-spanning civilization. A science-fictional analogue of the Encyclopedia Britannica. This term is used in many works by many authors, and prominently found in Douglas Adams' Hitch Hiker's Guide to the Galaxy series and Isaac Asimov's Foundation series.