What does "camel" mean?

Camel: (Naut.) A watertight structure (as a large box or boxes) used to assist a vessel in passing over a shoal or bar or in navigating shallow water. By admitting water, the camel or camels may be sunk and attached beneath or at the sides of a vessel, and when the water is pumped out the vessel is lifted. Camel bird (Zoöl.), the ostrich. -- Camel locust (Zoöl.), the mantis. -- Camel's thorn (Bot.), a low, leguminous shrub (Alhagi maurorum) of the Arabian desert, from which exudes a sweetish gum, which is one of the substances called manna.