according to a locked article in wikipedia, they are 'botanical fruits'
Many foods are botanically fruit but are treated as vegetables in cooking. These include cucurbits (e.g., squash, pumpkin, and cucumber), tomato, peas, beans, corn, eggplant
Corn is a fruit...?
heres the whole paragraph on it
Many foods are botanically fruit but are treated as vegetables in cooking. These include cucurbits (e.g., squash, pumpkin, and cucumber), tomato, peas, beans, corn, eggplant (aubergine), and sweet pepper, spices, such as allspice and chillies.[2] Occasionally, though rarely, a culinary "fruit" will not be a true fruit in the botanical sense. For example, rhubarb may be considered a fruit, though only the astringent petiole is edible.[7] In the commercial world, European Union rules define carrot as a fruit for the purposes of measuring the proportion of "fruit" contained in carrot jam.[8] In the culinary sense, a fruit is usually any sweet tasting plant product associated with seed(s), a vegetable is any savoury or less sweet plant product, and a nut any hard, oily, and shelled plant product.[9]
Although a nut is a type of fruit, it is also a popular term for edible seeds, such as peanut (which is actually a legume), pistachio and walnut.[10] Technically, a cereal grain is a fruit termed a caryopsis. However, the fruit wall is very thin and fused to the seed coat so almost all of the edible grain is actually a seed. Therefore, cereal grains, such as corn, wheat and rice are better considered edible seeds, although some references list them as fruits.[11] Edible gymnosperms seeds are often misleadingly given fruit names, e.g. pine nuts, ginkgo nuts, and juniper berries.