abbreviations
"Tr" - a traditional, usually academic definition or symbol
"Ex-" - example

ABCDEFGHIJKLMNOPQRSTUVWXYZ

OBERVATION COMPARISON
of patterns (of melo-rhytm, melo-harmony, or melo-lines) which recur, for better or for worse, in several tunes

OCTAVE
Tr- Distance, in the Quantitative Dimension of Pitch (frequency) see Interval

OFF-BEAT
The second half of any note-value

OPENING
One of the transformations in Melo-Harmony.

ORBIT(S)
The 4 members of a chord can be designated by the "orbit" in which they "gravitate" according to their degree of tension
     Orbit 0 is the COMMON TONE, with no tension at all.
     Orbit 1 is the PROPER TONE with very little tension
     Orbit 2 is the MEDIAN with considerably more tension
     Orbit 3 is the MOTRIX with high tension
     Orbit 4 is a chromatic version of Orbit 0 with very high tension (resolving to Orbit 3)

ORBIT 4
A form of Chromaticism (a Transformation in Harmony) in which Orbit 0 is chromaticized as it procures Orbit 3

ORCHESTRATION
The Art of organizing sound in the world of Energy (ie. Volume and Timbre), for performance. See the Orchestration Chapter