A gradual decline (in size or strength or power or number).

synonyms: ebb, wane.

Roget 36: decrease, diminution; lessening etc. v.; subtraction etc. 38; reduction, abatement, declension; shrinking etc. (contraction.) 195; coarctation^†; abridgment etc. (shortening) 201; extenuation.    subsidence, wane, ebb, decline; ebbing; descent etc. 306; decrement, reflux, depreciation; deterioration etc. 659; anticlimax; mitigation etc. (moderation) 174.    ... show more