A **scale** (Latin *scāla*, “ladder”) is the ordered collection of pitches to which a given passage of music refers. In theory, we generally write scales in ascending form within the span of one octave. In practice, we may encounter them in either ascending or descending forms, spanning anywhere from fragments to multiple octaves. Western music has traditionally relied on **heptatonic** (seven-note) scales. Of these, the most commonly encountered in the Common Practice Era are the [[Major Scale]] and the [[Minor Scales]].