Merriam-Webster's Collegiate® Dictionary, 11th Edition
DECREASE
I. verb (decreased; decreasing) see: crescent
Date: 14th century
intransitive verb to grow progressively less (as in size, amount, number, or intensity), transitive verb to cause to decrease, decreasingly adverb Synonyms: see: decrease
II. noun
Date: 14th century
the process of decreasing, an amount of diminution ; reduction