I'm trying to find out the correct name of this shape. Here are a few arranged in a circle:
Each of these shapes has four edges: two circular arcs and two straight line radii, making a closed shape.
I've been loosely calling this a sector, but I think the consensus is that sectors (also called slice or wedge) have three edges: two full radii as sides and a portion of a circle's circumference as the third edge. It's not a chord, obviously...
If there's no obvious name for this, any suggestions for a suitable one? I was thinking track or band, but not sure if these have better names already.

I would call it an annular sector (as in, a sector of an annulus). I don't think it really has a universally standard name. Apparently someone out there agrees with me.