Definition of cometarium in English:

cometarium

noun

Astronomy
historical
  • A mechanical device for demonstrating the appearance and motion of a comet moving in an elliptical orbit.

Origin

Mid 18th century; earliest use found in Benjamin Martin (bap. 1705, d. 1782), lecturer on science and maker of scientific instruments. From comet + -arium, after planetarium.

Pronunciation

cometarium

/ˌkɒmɪˈtɛːrɪəm/