ˌ ̷ ̷ ̷ ̷ˈles ə n(t)s noun
( -s )
Etymology: obsolesc ent + -ence
1.
a. : the process of becoming obsolete or the condition of being nearly obsolete
the gradual obsolescence of machinery
reduced to obsolescence
b. : the process of becoming or condition of being vestigial or nonfunctional
the obsolescence of the wings of some strictly terrestrial birds
2. : a factor included in depreciation to cover decline in value of fixed assets due to invention of new and better processes or machines, changes in demand, in design, or in the art, and other technical or legal changes but not to cover physical deterioration