Excavators are heavy construction equipment consisting of a boom, dipper (or stick), bucket and cab on a rotating platform known as the "house".The house sits atop an undercarriage with tracks or wheels. They are a natural progression from the steam shovels and often mistakenly called power shovels. All movement and functions of a hydraulic excavator are accomplished through the use of hydraulic fluid, with hydraulic cylinders and hydraulic motors.Due to the linear actuation of hydraulic cylinders, their mode of operation is fundamentally different from cable-operated excavators which use winches and steel ropes to accomplish the movements.

Excavators are also called diggers, JCBs(a proprietary name, in an example of a generic trademark), mechanical shovels, or 360-degree excavators (sometimes abbreviated simply to "360"). Tracked excavators are sometimes called "trackhoes" by analogy to the backhoe. In the UK, wheeled excavators are sometimes known as "rubber ducks".

Excavators are used in many ways:

• Digging of trenches, holes, foundations

• Material handling

• Brush cutting with hydraulic saw and mower attachments

• Forestry work

• Forestry mulching

• Demolition with hydraulic claw, cutter and breaker attachments

• Mining, especially, but not only open-pit mining

• River dredging

• Hydro excavation to access fragile underground infrastructure using high pressure water

• Driving piles, in conjunction with a pile driver

• Drilling shafts for footings and rock blasting, by use of an auger or hydraulic drill attachment

• Snow removal with snowplow and snow blower attachments

• Aircraft recycling