This technique relates to the following sections of the guidelines:
Use the span element with the title
attribute to provide generic meaning cues.
Words
that may have ambiguous meanings, because they are unfamiliar terms,
idioms, contractions, or have multiple meanings can be clarified with
the title attribute. If there is not a special element
for the type of disambiguation to be performed, apply this to a span
element.
Use the title attribute on a span to clarify an idiom.
<p>I hope I can <span title="sleep for awhile">catch some z's</span> on my
<span title="over night flight">red eye</span> home</p>