This is a type of chord used in musical harmony. It refers to a dominant of a degree other than the tonic, with V7/V, the dominant of the dominant, "being the most frequently encountered". The chord to which a secondary dominant progresses is a tonicized chord in that it is briefly treated as the tonic. Tonicizations longer than a phrase are modulations. The secondary dominant terminology is still used even if the chord resolution is nonfunctional.