three-kiloparsec arm

three-kiloparsec arm

[′thrē ¦kil·ō¦pär‚sek ′ärm]
(astronomy)
A region approximately 3 kiloparsecs from the galactic center that displays strong absorption in the 21-centimeter line of atomic hydrogen.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.