Word Study
obsolescence
CIDE DICTIONARY
obsolescence, n. [See Obsolescent.].
The state of becoming obsolete. [1913 Webster]
ROGET THESAURUS
obsolescence
Desuetude
N desuetude, disusage, obsolescence, disuse, want of habit, want of practice, inusitation, newness to, new brooms, infraction of usage, nonprevalence, a custom more honored in the breach than the obser, unaccustomed, unused, unwonted, unseasoned, uninured, unhabituated, untrained, new, green, unhackneyed, unusual, nonobservant, disused.For further exploring for "obsolescence" in Webster Dictionary Online