# What word is appropriate for a single-width slice of the third axis of data?

We have easy go-to terms for the X and Y axis, as row and column, respectively. However, I have never heard a similar term applying in the Z axis. Does such exist?

Cell is not appropriate, as as cell refers to a specific position, where the word in question would refer to some grouping of cells along the same position in the third axis.

Example:

Add another ______ to the input for temperature data

Row is to X axis as ______ is to Z axis.

• Well, in general, you would add another dimension to the data no matter how many you're starting with.
– Jim
Jan 16, 2016 at 1:47
• @Jim Dimension would refer to the addition of a Z axis to a set of data with rows and columns, but it doesn't fill the suggested role. Look at the example I gave - if you say "dimension" vs. "column", the meaning is vastly different.
– user121868
Jan 16, 2016 at 1:50
• Perhaps you could use "layer"
– Jim
Jan 16, 2016 at 1:55
• I think the title is part of what was causing confusion, since it seemed to be asking for a name for the third axis itself. I did an edit to clarify that, and to add the more logic-language example that helped me understand your question. I can't think of a better term than “single-width slice” for the title though, which is pretty awkward! I hope that edit helps though. Jan 16, 2016 at 2:18
• You would probably want to ask this on Mathematics SE. Spreadsheets use the idea of a page as a third dimension, graphics would use layers, and you could think of each as a plane where a point is define by (x,y,z). There would obviously be infinite many planes that could be defined.
– AMR
Jan 16, 2016 at 2:19

There is no standard term. There is no a strict association between "x axis" and "row". (For that matter, rows are generally indexed vertically, which would associate them with the y axis, not the x axis.) A figure (or feature space) with a y axis won't necessarily have anything you could point to as a "row".

Pixel-based images do have rows and columns that are often indexed with y,x values, in which case z often means depth (thus, "layers"), but that's specific to graphics.

If you're talking about matrices, your question was asked on reddit a while back, where the favored (but non-standard) term was "aisle":

As others have noted, Excel uses "sheets" for its third dimension, following the paper metaphor.

When working with three-dimensional data sets, the third dimension is defined by the type of data. For example, hyperspectral imagers create data cubes that are indexed by row (line), column, and band (wavelength or channel). A scientist could say

"Add another band to the data set for observations at 2.4 microns."

But that's specific to that data type, of course. Perhaps your best strategy would be to identify the appropriate specific type of dimension for your needs.

I would call it a tier.

column row tier
x y z
abscissa ordinate applicate

(Excuse the horrible formatting: Apparently this site doesn't use MathJax.)