1. A building for making observations, especially on the heavenly bodies.

Nuttall's Standard dictionary of the English language By Nuttall, P.Austin

• observitory,
• obsevatory,
• observaton,
• observator,
• observatoin,
• obseratory,
• obervatory,
• absolvatory,
• ibservatory,
• kbservatory,
• lbservatory,
• pbservatory,
• 0bservatory,
• 9bservatory,
• ovservatory,
• ohservatory,
• ogservatory,
• obeservatory,
• obsertvatory,
• observtory

• observation,
• observant,
• observantly,
• observed,
• observingly,
• observer,
• observance,
• observable,
• observational,
• observably,
• observing.

The adjective form of the word "observatory" is "observational".

The plural of the "observatory" can be the "observatories".

The singular of the "observatory" can be the "observatory".