[ramblenode]

"Grains" usually refers to cereal grains. Everything you listed except for oats is typically classified as a legume or a pulse, not a grain.

[queenkjuul]

I've never heard anyone refer to a food as a "pulse" as a lifelong American resident.

Granted, nobody has called a peanut a grain, but thinking about it, i don't really see why not to. But a pulse?

[cogman10]

Legumes are grains. It's a sub category just like cereal is a sub category. They are all grains.

[TGower]

Only in the "cucumbers are fruit" botanically technically correct but incorrect from common usage standpoint.