What is the rotating part of an excavator called?

Excavators (hydraulic) 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. All movement and functions of a hydraulic excavator are accomplished through the use of hydraulic fluid, with hydraulic cylinders and hydraulic motors. [1] Below are some of the common parts of an excavator:

1. Boom
2. Boom Cylinder
3. Bottom Roller(s)
4. Bucket
5. Bucket Cylinder
6. Cab, ROPS
7. Car Body
8. Dipper, Arm, Stick, Crowd Cylinder
9. Engine
10. Final Drive, Reduction Assembly
11. H-Link
12. Main Control Valve
13. Main Hydraulic Pump
14. Side Link, Dog Bones
15. Slew Ring, Swing Gear, Swing Bearing
16. Sprocket
17. Swing Reducer, Swing Drive & Motor
18. Track Adjuster, Tensioner
19. Track Chain, Rails
20. Track Pad, Grouser Pad