Definition: The octave is the natural phenomenon where the 'same' sound occurs on another level, and is characterized by a frequency ration of 2:1
Further info: It is the most consonant interval and consecutive octaves should be avoided in part writing because of sonority.
Taken from: Unit 6, p.62
Definition: In mediaeval times, melodies could be doubled in fifths and octaves (this was called 'Organum') and the effect was considered acceptable. Indeed, it was probably attractive in large, resonant buildings.
Taken from: Unit 12, p.47
Definition: 'Ornaments' are a particular feature of 17th and 18th Century music.
The thing to remember, however, is that ornaments are ornamental, even though they may be an essential part of the character of a musical style.
See also: Appoggiatura, Acciaccatura, Trill, Mordent , Mordent - inverted, Turn and Turn - inverted
Taken from: Unit 9, p.6 and Unit 17, p.25
Definition: Probablyy the simplest type of variation is that in which a short melody or rhythm is repeated several times in its entirety, anywhere in the texture of a piece of music. This is called an ostinato (Italian for 'obstinate')
Examples: Ravel's 'Bolero' - the snare drum rhythm is repeated throughout
Taken from: Unit 10, p.31
Definition: ... below this sign, the music sounds one octave higher than written. You will see this useful sign quite frequently in all types of music. Sometimes it is printed as 8va (with a superscript 'va'), standing for ottava.
Taken from: Unit 14, p.9