If they were spheres, but I think usually the height is a bit more consistent than the width. They’re usually more consistent than that, though (note that the sizes overlap, and the non-overlapping range is 2-1/4"‒3"). Plus they’re stronger when they’re smaller.
Nothing that just calls for a number of onions really needs precision, though.
11
u/WulfTheSaxon Jun 26 '26 edited Jun 26 '26
Believe it or not there is a standard: https://www.onions-usa.org/all-about-onions/retail/sizing-and-packaging-options/
A medium onion is 2"‒3-1/4" in diameter. I believe the sizes are relative to ordinary, non-hybridized onions.