observatorium means an observatory. Lexicurio rates it Sui generis — a strength score of 100 out of 100.
Etymology
From Latin observātōrium.
noun
- An observatory.“The obſervatorium, built by Chriſtian VI. in ſuch a manner that a coach and horſes may aſcend to the top; here they keep the public library, and Tycho Brahe’s mathematical inſtruments, eſpecially his famous celeſtial globes, which are three yards thick in diameter.”