<p><strong>Noun</strong></p><ul><li>the act or process of alternating or the state of being alternated.</li><li>alternate succession; repeated rotation: the alternation of the seasons.</li><li>a single fluctuation in the absolute value of an alternating current or voltage from zero to a maximum and back to zero, being equal to one half cycle.</li><li>variation in the form of a linguistic unit as it occurs in different environments or under different conditions, as between the -ed and -en forms of the past participle in danced and spoken or between the (t) and (d) pronunciations of the past tense suffix -ed in hopped and rubbed.</li></ul>