Also known as a mother-in-law cottage, a small second house on the same lot as the 'big' house.
I had hoped to put in a 2 br cottage and rent it out, doing my bit to help relieve the city's chronic housing shortage, and make enough to cover the mortgages. (And cover more ground so there would be less to mow!)
Yes, I should have known what is a granny unit. My Aunt and Uncle living in Long Beach, Ca. had a garage apartment on their property that generated much extra income for them over the years.