Source : Webster's Revised Unabridged Dictionary (1913)

Extendible \Ex*tend"i*ble\, a.
   1. Capable of being extended, susceptible of being stretched,
      extended, enlarged, widened, or expanded.

   2. (Law) Liable to be taken by a writ of extent.

Source : WordNet®

extendible
     adj : capable of being lengthened [syn: {extendable}]