7 C.F.R. § 958.9
Grade means any of the officially established grades of onions, and size means any of the officially established sizes of onions, as set forth in:
(b) Any other United States Standards, or State of Idaho or Oregon Standards for onions, or amendments thereto, or modifications thereof, or variations based thereon.
The term size also includes any of the sizes recognized by the onion trade in the production area.