Depth contour or line on a chart that connects points of equal depth.
In hydrologic terms, an imaginary line on the earth's surface or a line on a map connecting all points which are the same vertical distance above the upper or lower surface of a water-bearing formation or aquifer
Line connecting points of equal WATER DEPTH on a chart; a seabed contour.
Lines on a map connecting points of equal water depth.
contour line linking regions of the same depth.
An underwater contour line: a line that connects areas of equal depth.
A line on a map or chart that connects all points having the same depth below the surface of a body of water; also, having constant depth.
(Isobathe) Line connecting points of equal depth in a water mass.(Translated from Grand dictionnaire terminologique. Office de la langue française and Sémantix. 2000.)