Hȳ-drŏg'ra-phy, n.

n. [Fr. hydrographie, from Gr. ὕδωρ, water, and γράφειν, to write, describe.]

1. The art of measuring and describing the sea, lakes, rivers, and other waters.
2. That branch of nautical surveying which embraces the determination of the contour of the bottom of a harbor or other sheet of water, the depth of soundings, the position of channels and shoals, with the construction of charts exhibiting these particulars.