obsolete

from The American Heritage® Dictionary of the English Language, 5th Edition.

• adjective No longer in use.
• adjective Outmoded in design, style, or construction.
• adjective Biology Vestigial or rudimentary, especially in comparison with related or ancestral species, as the tailbone of an ape. Used of an organ or other part of an organism.
• transitive verb To cause to become obsolete.

from The Century Dictionary.

• In botany, notingan organ which is rudimentary or scarcely apparent.
• Gone out of use; no longer in use: as, an obsolete word; an obsolete custom; an obsolete law. Abbreviated obsolete
• In descriptive zoöl., indistinct; not clearly or sharply marked; applied to colors, faded, dim: as, an obsolete purple; applied to ornaments or organs, very imperfectly developed, hardly perceptible: as, obsolete striæ, spines, ocelli.
• To become obsolete; pass out of use.
• To make obsolete; render disused.

from the GNU version of the Collaborative International Dictionary of English.

• intransitive verb rare To become obsolete; to go out of use.
• adjective No longer in use; gone into disuse; disused; neglected; ; -- applied chiefly to words, writings, or observances.
• adjective (Biol.) Not very distinct; obscure; rudimental; imperfectly developed; abortive.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• adjective of words, etc. no longer in use; gone into disuse; disused or neglected (often by preference for something newer, which replaces the subject).
• adjective biology Imperfectly developed; not very distinct.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• adjective no longer in use