Cultivar is a created term used in agriculture, a combination of the words "cultivated" and "variety". A cultivar is a variety which has been propagated to a standardized combination of desirable characteristics.
A cultivar can be an assexually propagated clone, as with many fruits, where selected cultivars are grafted or budded onto rootstocks.
Cultivars may also be open pollinated, which refers to a history of cross pollination with plants that are sufficiently similar that the characteristics of the variety have become standardized. With open pollinated cultivars, plant breeders will remove any plants from the breeding population that exhibit different characteristics, however, there is a tendency to drift, due to cross pollination with other cultivars that may be nearby, or with the expression of recessive genes. Open pollinated cultivars with a long history are often referred to as "heirloom" varieties.
Cultivars may also be hybrids, which must be recreated each generation by seed companies, by deliberate crossing of two (sometimes more) lines that have been developed over time.