From Latin obsolescere (“to wear out, fall into disuse, grow old, decay”), inceptive of obsolere (“to wear out, decay”) (rare), apparently from ob (“before”) + solere (“to be wont”); or else from obs-, a form of ob- + olere (“to grow”) (compare adolescent).
- To become obsolete.
Related terms 
- obsolesce in Webster’s Revised Unabridged Dictionary, G. & C. Merriam, 1913
- obsolesce in The Century Dictionary, The Century Co., New York, 1911
- obsolesce at OneLook Dictionary Search
- second-person singular present active imperative of obsolescō