a fruit having enlarged accessory structures in addition to those formed from the ovary, as the strawberry, in which the fleshy tissue is the enlarged receptacle and the true fruits are the small, dry achenes borne on its surface
See accessory fruit in American Heritage Dictionary 4
noun
A fruit, such as the pear or strawberry, that develops from a ripened ovary or ovaries but includes a significant portion derived from nonovarian tissue. Also called false fruit, pseudocarp.