[led] 
| a line by which a lead is lowered into the water to take soundings: in deep-sea practice, divided into levels one fathom apart, variously treated as marks and deeps. |
| lead line (lěd) n. See sounding line. [From the use of lead weights for making soundings.] |
| sounding line n. A line marked at intervals of fathoms and weighted at one end, used to determine the depth of water. Also called lead line. |
lead line n.
An irregular dark deposit in the gums occurring in lead poisoning.