Longman Dictionary of Contemporary English
Wiktionary
n. an oven that features fans to recirculate heated air to accelerate heating provided by traditional radiant heat sources found in the oven
Wikipedia
A convection oven (also known as a fan-assisted oven or simply a fan oven) is an oven that has fans to circulate air around food. Conventional ovens, which do not have fans, rely primarily on radiation from the oven walls, and to a lesser extent, on natural convection caused by temperature differences within the oven, to transfer heat to food. In contrast, the fans in convection ovens allow more heat to be transferred via convective heat transfer.
Convection ovens distribute heat evenly around the food, removing the blanket of cooler air that surrounds food when it is first placed in an oven and allowing food to cook more evenly in less time and at a lower temperature than in a conventional oven.