# Is there a name for filled square?

When talking about circles, a "circle" refers merely to a line in the shape of a circle, whereas "disk" (or "disc") refers to a "filled circle". Is there a similar distinction for squares or rectangles?

• @Adam thanks for the tags, I seriously had no idea how to tag this. Commented Oct 18, 2015 at 15:49

"disc" means "thin, flat, circular object" and is mostly applied to 3D objects. "Circle" is for 2D-ish circular things.

In math, "disc" has its own meaning; the meaning you mentioned, as well as the normal meaning.

Names of shapes cover both definitions you provide ("a line in the shape of X" and "filled X"), except circle (and in non-rigorous talk, they get conflated too).

• What would be a natural succinct way of referring to the two variants (filled vs. not)? Commented Oct 16, 2015 at 15:30
• As you draw the line in the shape of a circle, the resulting shape is a circle, with (semantically) blank filling. As a result you get a semantic merger. Commented Oct 16, 2015 at 16:35
• Try using filled/solid and hollow. Commented Oct 16, 2015 at 18:42
• @Nihilist_Frost Note: "Disk" has a distinct mathematical meaning (which I'm pretty sure the question is referring to) that doesn't relate to 3D objects, but rather a circular area on a plane (i.e. 2D): en.wikipedia.org/wiki/Disk_%28mathematics%29 . But I can't think of any such term for any other shape either. Commented Oct 16, 2015 at 18:43
• @jezW How about the distinction between annulus, and concentric circles? Perhaps we don't specify a name for "filled square" because topologically, that's the same thing as a disk.