1. (n.) A general or comprehensive view.

2. (n.) an optical instrument of tubular shape containing an arrangement of lenses and mirrors (or prisms), allowing a person to observe a field of view otherwise obstructed, as beyond an obstructing object or (as in submarines) above the surface of the water.

Aqua-Lung air cylinder aquascope bathyscaphe bathysphere benthoscope diving bell diving boat diving chamber diving goggles diving helmet diving hood diving mask diving suit scuba snorkel submarine swim fins wet suit