ob•so•leteˌɒb səˈlit, ˈɒb səˌlit(adj.; v.)-let•ed, -let•ing.

1. (adj.)no longer in general use:

   obsolete customs.

2. of a discarded or outmoded type:

   an obsolete battleship.

3. (of a linguistic form) no longer in use, esp., out of use for at least the past century: used in this dictionary to indicate that a word has not been in widespread use since c1750.

   Category: Language/Linguistics

   Ref: Abbr.: Obs.

4. rudimentary in comparison with the corresponding part or trait in related species or in individuals of the opposite sex.

   Category: Developmental Biology

5. (v.t.)to make obsolete; antiquate.

Origin of obsolete:

1570–80; < L obsolētus, ptp. of obsolēscere to fall into disuse, perh. =ob-ob-sol(ēre) to be accustomed to +-ēscere-esce

ob`so•lete′ness(n.)