#power_shovel__powershovel__excavator__digger__shovel  a machine for excavating
  supertype:  machine  any mechanical or electrical device that transmits or modifies energy to perform or assist in the performance of human tasks
  subtype:  backhoe  an excavator whose shovel bucket is attached to a hinged boom and is drawn backward to move earth
  subtype:  dredge  a power shovel to remove material from a channel or riverbed
  subtype:  steam_shovel__steamshovel  a power shovel that is driven by steam

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