tonica

Tonica is a term used in music theory to designate the tonic, the central pitch and primary triad that defines a key. In most Western tonal systems the tonica is the first degree of a major or minor scale and serves as the anchor around which melodies and harmonies are organized. The tonica provides a sense of home and acts as the target of cadences.

Functionally, the tonica is the I chord in major keys and the i chord in minor keys, and it is the point to which other chords tend to resolve, such as in a dominant-to-tonica cadence. In analysis, identifying the tonica helps determine the key and the tonal center of a piece. In C major, for example, C is the tonica; in A minor, A is the tonica.

Origin and usage: The term comes from Italian tonico/tonica, and related forms appear in several languages with variations such as tónica (Spanish/Portuguese) or tonique (French). In these languages the concept may refer to the musical tonic as well as, in some contexts, the tonal center of a phrase or key.

Other contexts: In linguistics, a closely related idea is the tonic or tónica, referring to the syllable bearing the primary stress in speech. This is distinct from the musical sense, though the terms share a common root related to emphasis and importance.