Copernican Hypothesis. The view held by Copernicus regarding the solar system. He called it an 'hypothesis' to avoid antagonising the Pope of Rome.
Copernican System. Placed Sun in centre and relegated Earth and planets to subordinate positions. Considered Earth and planets to be joined to Sun by bars. Until Kepler and Newton proved the falsity of this latter assumption the view of Copernicus was generally accepted.
Copernican Theory.Later name for 'Copernican hypothesis'.
Copper. Soft and ductile metal that forms base for brass or bronze. Is good conductor of heat and electricity. As it slowly exfoliates in sea water, it prevents accumulation of fouling when used as sheathing on underwater body of a ship.