1. A building, place, or institution designed and equipped for making observations of astronomical, meteorological, or other natural phenomena.
2. A structure overlooking an extensive view.

[French observatoire (influenced by CONSERVATORY), from observer, to observe, from Old French. See observe.]

The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.