Hi Paul, not an expert but there are many references that back this up.

To my understanding it has to do with dimming (see Cillie's proposal), which seems the be effect of partialization.

Ciao!

In this kind of application, the MOSFET is used like a controlled switch aiming to partialize the sinusoidal voltage to supply the load (led or halogen lamp), with a corresponding variation in brightness. Recent changes to the lighting industry are pushing LED on the market thanks to the improvements to this technology to push the efficiency and durability to new standards.
https://eepower.com/technical-articles/right-technology-for-...
The adjustment of the lamp load is achieved in dimmers by "partialization" of the semonde. A dimmer that partializes the starting part of the semionda uses the Leading Edge method, while a dimmer that partializes the end part uses the Trailing Edge method.
https://www.amazon.co.uk/15-61-8-230-0500-Finder-15-51-8-Clo...

As far as lighting is concerned, the special division of the filament into four separate compartments, each of which can be partialized and switched on or off
https://patents.google.com/patent/DE202011101889U1/en

UV LED Droled lamp with its partialized emission window allows you to adjust the switching on/off and the intensity of certain segments of the lamp, based on the required print width.
https://www.photoelcuring.com/en/application-areas/printing/...

Remote control to command the control unit: insertion, disarm, partialization and other applications.
https://www.elmospa.com/en/products/active/intrusion-detecti...

In LED retrofit installations there may be a flux regulator for discharge lamps. With this option, the LED fixture follows the voltage regulation carried out in the system, thereby varying the power supply current of the LEDs. It is thus possible to combine HID luminaires with LED luminaires in the same system by exploiting existing energy-saving systems. Operation is guaranteed only in the presence of amplitude modulation regulators and not on phase partialization (cutoff).
https://www.aecilluminazione.com/smart-public-lighting-contr...