In California English, a strip mall or shopping center defined by unenclosed stores with external entrances, separated from the street by a large parking lot. A normal plaza is anchored by a grocery store, a drugstore, or both. A power plaza is anchored by big-box stores. Many smaller plazas have no anchor store, just a selection of tanning salons, gift shops, and takeaway restaurants.
That plaza used to have a lot of cute stores, but then Alberton's left, and now you have to be Cambodian to even read the signs.