Dynamics--piano, forte: The volume or loudness of sound, with "piano" meaning "soft," and "forte" meaning "loud."
Bitonality: The simultaneous use of two different tonalities or keys. This may occur briefly or over an extended span of time within a composition.
Interval: The distance between two pitches; the relationship between two pitches, identifiable by a characteristic sound. Some common intervals are half-step (on a piano: from a black key to a white key or vice versa), whole step (one step in the scale, from white key to white key or black key to black key), third (three steps apart in the scale), fourth, fifth, and octave (eight steps apart in the scale).
Arpeggio: A chord whose pitches are sounded successively, usually from lowest to highest, rather than simultaneously.
Modernist music: Music of the twentieth century that
is marked by its departure from the tonal system used in music
of the 18th- and 19th- centuries. The abandonment of that system
made new compositional possibilities available to composers, some
of which were: atonality, bitonality, pastiche (where a composer
might mix together radically contrasting musical styles, materials,
and techniques in unprecedented combinations), and neoclassicism,
which reemphasized connections with older Western musical tradition
not, however, by a return to traditional tonality but by favoring
formal structures based on Baroque or Classical models.