n. One who or that which excavates.n. Specifically— A horse- or steam-power machine for digging, moving, or transporting loose gravel, sand, or soil. The ditch-excavator is practically a scoop-plow that loosens the sod, while an endless band armed with buckets scoops the soil, raises it, and throws it out at one side of the machine. The transporting excavator loosens the soil and raises it upon a traveling apron to a hopper. When the hopper is full the machine is dragged away upon a carrying-line to the place where the load is to be discharged.n. An instrument used by dentists in removing carious parts of a tooth preparatory to filling it.n. A modified form of dredging-machine used in digging irrigation canals. It consists of a chain-and-bucket conveyer mounted on a trolley that moves on rails laid on a traveling crane. Tracks are laid on each side of the canal, and upon these the crane moves. The conveyer, supported by a derrick, cuts into the soil, both below and above the water, and lifts it to chutes that discharge it on the banks at each side. Since the conveyer travels on the crane transversely to the length of the canal all the soil can be excavated and the crane advanced on the tracks as fast as the canal is dredged out.