is a specific kind of: jack, laborer, labourer, manual laborer.

is a broader term that covers: ditch digger, mud digger | trencher.

derivation: dig, dig out.

is a specific kind of: machine.

is a broader term that covers: backhoe | dredge | steam shovel.

derivation: cut into, delve, dig, turn over | dig, dig out | excavate | shovel.