An instrument for measuring the depth of a body of water: In her oceanography class at college, Susan learned that a bathometer was used to ascertain the depth of the sea, but it is rarely used in the present time.

A sounding line was used previously with a bathymeter, but it proved to be quite difficult and a time-consuming procedure.

The bathometer does not require a line to extend to the bottom because it measures the difference in the gravitational effect of the water surface and of solid ground.

1. An instrument for recording contours of deep oceans: Besides being used for deep-sea sounding and measuring, a bathymeter is also good for finding out the topography of the bottom surface of the seas.
2. A simple device used for gaging the deepness of liquids in tanks and wells: Mr. Smart used a bathymeter to find out how much water was left in his waterhole on the farm.