In music, tonicization is the treatment of a pitch other than the overall tonic as a temporary tonic in a composition. Tonicization is achieved through the use of the scale and harmonies of the tonicized key. The most common method of tonicization uses leading tones, dominant-tonic chord progressions, or a combination thereof. Tonicization is an example of tonal chromaticism. Tonicization is not very different from modulation, because (according to Schenker),"there's no such thing as a modulation in music", because a modulation is nothing more than a long tonicization, in which the influence of the previous key is still evident.

A tonicized chord is a chord to which a secondary dominant progresses. For example ii in V/ii. Only major and minor chords may be tonicized. Though perceptions vary as a general rule if a chord is treated as the tonic for longer than a phrase then the treatment is considered a modulation.

Read more about Tonicization:  Change of Scale, Use of Secondary Harmonies

Other articles related to "tonicization, tonicizations":

Tonicization - Use of Secondary Harmonies
... Introducing altered tones melodically often produces only a weak feeling of tonicization ... Stronger tonicizations are frequently achieved by borrowing not only pitches from the tonicized key, but also chords (known as "secondary chords" or "sec ... For example, if the original tonic is C Major and a tonicization of F Major (the subdominant and 4th scale degree of C Major) is desired, one could use the V7 chord of F Major (which is C7) as a secondary ...
... Tonicization or modulation to the mediant is quite common in pieces written in the minor mode, and usually serves as the second theme group in sonata forms, since it is very easy to tonicize III in ... Tonicization of III in major is quite rare in classical harmony, compared with, say, modulation to the V in major, but mediant tonicization in major is an important ...