A Retirement home is a place of residence intended for the elderly.
The usual pattern is that each person or couple in the home has an apartment-style room or suite of rooms. Additional facilities are provided within the building. Often this includes facilities for meals, gathering, recreation, and some form of care. The level of facilities varies enormously.
A retirement home differs from a nursing home primarily in the level of medical care given.
A place in a retirement home can be paid for on a rental basis, like an apartment, or can be bought in perpetuity on the same basis as a condominium.