1.Variations within a gait. The named paces are: at walk: collected, medium, extended, free; at trot and canter: collected, working, lengthening of stride, medium, extended. Each named pace is characterized by a given length of stride as well as by other attributes listed under their individual definitions.
2. Gait in which the lateral pairs of legs move in unison (not considered a dressage gait). If the lateral pairs move somewhat but not entirely synchronously, this is sometimes called “pacey” or “pacing tendency” or “lateral” or “lateral tendency.” This faulty lateral tendency may be seen in walk or canter.
Note: The U.S. uses the terms “gait and pace” where the FEI uses the terms “pace and variation.”
Full glossary: http://bit.ly/2019USDFGlossary