Just curious, what do you mean by "culinary standpoint".
When it comes to fruits, vegetables, and grains there are three different ways to view them; culinary (how you cook them), botanical (what class they scientifically fall into), and glycemic or nutritional (how your body processes them).
Beans, squash, cucumbers, tomatoes, apples, pears, grapes, oranges anything where we eat the flesh that is around the seeds are all fruits botanically. However, you do not prepare a green bean and an orange in the same way. They taste different (savory/bitter vs. sweet), have different textures, and react to certain cooking methods differently. They are also treated differently by your body during digestion. An orange will raise your blood sugar much higher, while the beans will provide more fiber and an entirely different set of nutritional components.
In cooking you treat corn as both a grain and a vegetable. When prepared from raw and whole (such as on the cob or from a can), corn is prepared as a you would a vegetable. We sauté it, grill it, fry it, bake it, boil it, etc. These are things you would not do with raw whole wheat or most other grains. In order to cook with corn the way you would a grain you must dry it and grind it first, just as we do with most forms of grains. Of the few grains that we can straight boil, none of them maintain their form as corn does.
Another way to determine the culinary designation of a plant is to see where you buy it in the grocery. Corn is sold with the produce (fruit and vegetables) when raw, or in the vegetables when whole and in a can. Canned fruit are in a different area. You will not find whole corn in the bread, flour, etc. sections. You will find corn flour, corn meal, and so forth, but none of that can be prepared the way you can a vegetable.