According to good ol' Wikipedia, I am, "...the unripe fruits of any kind of bean, including [list of beans], whose pods are also usually called string beans in the northeastern United States, but can also go by snap beans." Green beans taste delicious, so go eat me.* Also, if you eat me and other happy veggies and fruits and stay away from junk (food) you might not add to America's widespread obesity problem, so...HUZZAH!
*Don't eat canned green beans. Those are nasty. Do, however, eat fresh green beans (steamed, preferably), or green beans in green bean casserole. Although, are canned green beans used in that? That's the only time canned green beans are acceptable. Frozen green beans are permissible only if one cannot buy fresh ones.