'PRAT' is an abbreviation of a long-winded way of saying 'rhythm'. How could concepts of pace and timing not be included in the plain idea of rhythm?
I refer to my OED online:
"Rhythm: 'That feature of musical composition which depends on the systematic grouping of notes according to their duration. b. Kind of structure as determined by the arrangement of such groups.'
I refer to my OED online:
"Rhythm: 'That feature of musical composition which depends on the systematic grouping of notes according to their duration. b. Kind of structure as determined by the arrangement of such groups.'