Hello. In America a railroad crossing is often called a grade crossing.

I know what "crossing" means. But what is "grade"?

Why do you call "grade"?

Thank you.
I had to check Wikipedia for this. Apparently a grade crossing is one where the railroad tracks cross the road on the same level -- not below the road with a tunnel or above the road with a bridge. "Grade" here means something like "level". It can also mean "slope" -- sometimes in the mountains there will be highway signs warning of "steep grade."
I'm glad khoff looked that up. I've never heard it called that.
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Your explanation is very helpful. Thank you!
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