As Tomas says, Bob Katz has been using the term, "microdynamics," to refer to the crest factor of transients. "Macrodynamics" refers to the difference between the fortissimo and the pianissimo passages. The difference in level between a quiet intro and a loud chorus illustrates one case of macrodynamics. The difference between the RMS level of the mix and the peak level for a single kick drum "note," or single hand clap*, would be one case of microdynamics.
*not the quiet kind where only one hand is clapping, of course. (;
From
http://www.ultimateavmag.com/ in their article on the Bel Canto Evo2 amplifier:
"...Audiophiles often talk about micro- and macrodynamics. Macrodynamics refers to a system's total dynamic range from loud to soft, while microdynamics concerns the subtle differences between small changes in volume. Most decent amplifiers can get the macrodynamics right, but mastering microdynamics separates the merely good amplifiers from the truly great."
Andrew