Google Play Services
Definition
A background system service and API package for the Android operating system that facilitates core functionality like app updates, security authentication, synchronization, and location services.
The invisible, battery-draining digital glue that somehow keeps most of the Android ecosystem from crumbling into a heap of incompatible icons.
Examples
I told my phone that Google Play Services is just background magic, but it clearly thinks it is a full-time high-intensity workout for the battery.
If deleting cache for Google Play Services was an Olympic sport, I suspect the entire Android user base would be taking home gold medals.
I like to treat Google Play Services like a moody roommate who demands all the resources but only does the chores when it feels like it.