Z

z-

Hyphenate all words that begin with z used as a separate letter, such as z-coordinate, z-test and z-axis.

Don’t use italic formatting for the z in these words unless the entire word is italic.

z-axis

Use lowercase and hyphenate.

Don’t use italic formatting for the z in z-axis unless the entire word is italic.

zero, zeros

Use zeros, not zeroes, as the plural of zero.

When a measurement is zero, use the plural form of the spelled-out unit of measurement.

Examples

zip

Don’t use a filename extension to refer to a type of file. For example, use zip file rather than .zip file.

Don’t use zip or unzip as a verb. Instead, use compress and extract.

For more information, see Referring to file types.

ZIP code

OK to use in content intended for US locales and audiences. Otherwise, use postal code.

Use uppercase capitalization for ZIP.

zoom

OK to use zoom, zoom in, zoom out.

For more information, see Interaction verbs.