I'm no expert, but, I was told this term describes when a senior goes to a facility and despite their decline in health or progression in dementia, they can remain the same place, without having to relocate to another type of long term care facility.
Aging in Place means you are in your OWN home, not a facility. It means that you will be remaining in your own home for the later years of your life; not moving into a smaller home, assisted living, or a retirement community etc.