In arabic the word "dar" means house and the word "ryad" means garden. Formerly, the word ryad (or riad) was used only for houses with a garden. A house built around a central patio without a garden was called a dar. But today many dars are called riads whether they have a garden or not.
The guesthouses, hotels and apartments proposed for rent under the name of dars or riads are former traditional family houses
or sometimes palaces restored and adapted to receive paying guests.
All these riads, dars and palaces offer the experience of a stay in an architectural environment which is traditional (even sometimes historical) and typical of the medina of Fez, but there are big differences in terms of style, decor, character, size, location, quality and price.
Therefore it is important to compare and look for precise information to make sure you will book at a place meeting your expectations.