|bathymetry (bə-thĭm'ĭ-trē) Pronunciation Key
The measurement of the depth of bodies of water, particularly of oceans and seas.
measurement of ocean depth. The earliest technique involved lowering a heavy rope or cable of known length over the side of a ship, then measuring the amount needed to reach the bottom. Tedious and frequently inaccurate, this method yielded the depth at only a single point rather than a continuous measurement; inaccuracies arose because the rope did not necessarily travel straight to the bottom but instead might be deflected by subsurface currents or movements of the vessel.
Learn more about bathymetry with a free trial on Britannica.com.