Final answer:
A legal, single condominium for sale above a non-sale retail store is classified as a mixed-use property, combining residential and commercial uses.
Step-by-step explanation:
The classification of a legal, single condominium for sale that is located above a retail store which is not for sale would fall under mixed-use property. This type of property combines at least two different uses within the same building, often residential and commercial.
The condominium itself would represent a residential portion of the property, while the retail store would be classified as the commercial portion. The ownership of the two spaces is typically divided into a condominium arrangement for the residential unit, which would be sold or bought independently of the commercial space beneath it.