Drum/Sample Kits vs. Expansions

Can someone explain the difference to a newbie? Is there a preference amongst the MPC community?

Drum Kit = a collection of drum samples mapped to the pads, typically in a DRUM type program.
Sample Kit = a mixture of drums, percussion, musical one shots, even loops etc. Often just mapped to bank A in a DRUM program. Used in the MPC library demo kits.
Expansions = a bunch of kits, samples, loops, instruments, projects, sequences etc collated into a single 'pack', usually based around a 'theme' (e.g. boom bap expansion, analog synth expansion etc). For use in the dedicated Expansion browser.

However, many people often use the terms 'kits', 'drum kits' and 'sample kits' interchangeably to just refer to any DRUM program containing samples assigned to pads.

Most MPC users these days will expect commercial sound packs to be in 'expansion' format and contain multiple kits and/or instruments.