The word-spacing property controls the
amount of spacing in between words. This property can be set in any one
of the available CSS length units: px, %, em, in, cm, mm, pt, pc, and ex.
One important note to mention about this property is that any amount you
specify will be in addition to the default amount
of spacing between words. Negative lengths are permitted.
Note: Word spacing may also be affected by
justification (see the text-align property).
Tip:
This property is optional. If you would like to include it in your
generated CSS code simply check the checkbox by it's name (to enable it)
and then enter in a value and choose a CSS length unit. For example, I
may type in "1" for it's value and "px" for it's length unit, making
it's total value "1px". That means the spacing in between words will be
"1px" (the amount I specified) plus whatever their normal or default
spacing was. If you would like to decrease the amount of spacing in
between words just use a negative amount. For an explanation of all the
different CSS length units, consult the section of the manual entitled
CSS Length Units.
Read
an official description of the word-spacing property from the W3C