Definition of degressions:
(n) :
(economics) Degressive taxation, a system of progressive decreases in a rate of taxation (as tariffs etc.) below certain benchmarks.
(n) :
(publishing) Degressive description, a system of varying descriptions of a book in accordance to its importance or available space.
(n) :
(obsolete) Descent, the act of descending.
(n) :
Obsolete spelling of digression. [An aside, an act of straying from the main subject in speech or writing.]