Rose could say she is essential in that she provides plumbing-type services.
The following are REAL terms plumbers use:
Angular Discharge Tube
Backflow
Back Flow Preventer
Back Siphonage
Ball Check Valve
Ballcock
Blowbag
Cleanout Plug
Closet Bend
Cock
Coupling
Dip Tube
Direct Tap
Discharge Tube
Female Fitting
Finish Plumbing
Float Ball
French Drain
Gas Cock
Horizontal Run
Johnni-bolts
Knockout Plug
Lock Nut
Male Threads
Malleable Fittings
Multi-Stage Pump
Nipple
O-Ring
Packing Nut
Pipe Dope
Plumber's Putty
Reamer
Rigid Pipe
Rim Holes
Self-Rimming Sink
Service Entrance
Stack
Stand Pipe
Thermocouple
Some of those terms apply to Rose I would think...