Observatory

·noun A place or building for making observations on the heavenly bodies.

II. Observatory ·noun A place, as an elevated chamber, from which a view may be observed or commanded.

III. Observatory ·noun A lookout on a flank of a battery whence an officer can note the range and effect of the fire.

IV. Observatory ·noun A building fitted with instruments for making systematic observations of any particular class or series of natural phenomena.