If you take a rectangle and divide it into four equal pieces with two perpendicular lines, you have created quadrants:

enter image description here

But what if you divide the rectangle into nine equal pieces with two sets of two mutually parallel lines like this:

enter image description here

Is there a name for these pieces? An example sentence would be:

The dart has struck the middle ______.

If there are six pieces they can be called sextants, and if there are eight pieces they can be called octants, but the word "nonant" doesn't seem to exist, at least not with this meaning.

edit: I'm specifically looking for a mathematical term to refer to the area that the rectangle is divided into, so a word analogous to "quarter" but referring to nine pieces doesn't answer my question. (See this.)

  • 1
    The dart has struck the middle square. – user66974 Oct 16 '16 at 21:57
  • Urban Dictionary lists this meaning for 'nonant', but I'd want to see it in OED (other respectable dictionaries seem to omit it, as you suggest). – Edwin Ashworth Oct 16 '16 at 22:00
  • "Square" in this case is not analogous to quadrant, because it neither implies there being a certain number of pieces nor that something has been divided. A better fit would be "section" but I was hoping there was a good word that indicated one of nine pieces of a whole as pictured. – GuyGizmo Oct 16 '16 at 22:02
  • OED lists octant, but not nonant, decant, undecant or duodecant. I didn't look any further. Decant is listed as a verb, of course. This would suggest that the number of historical uses of nonant is vanishingly small. – Andrew Leach Oct 16 '16 at 22:26
  • I tried looking up the possible smaller odd divisions, "septant/heptant", "pentant/quintant" and "triant/treant" and only found "quintant" which was a 17th century instrument similar to a sextant but based on an angle of 72 degrees rather than 60. My guess is that "quadrant", "sextant", "octant" and, to some extent "quintant" were words which were useful in some version of general speech and so became established whereas the others were not generally useful and so did not become established. – BoldBen Oct 17 '16 at 7:50

Consider ninth, which means

each of nine equal parts into which something is or may be divided.

It is used to refer to the kind of section you're after in this mathematical text, albeit with scare quotes. Also, "middle ninth square" is used here.

In your sentence:

The dart has struck the middle ninth.

  • Yes, but reading that sentence you would probably think: "the middle what?" :) – user66974 Oct 17 '16 at 7:10

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