Source : Webster's Revised Unabridged Dictionary (1913)

Rudimentary \Ru`di*men"ta*ry\, a. [Cf. F. rudimentaire.]
   1. Of or pertaining to rudiments; consisting in first
      principles; elementary; initial; as, rudimental essays.

   2. (Biol.) Very imperfectly developed; in an early stage of
      development; embryonic.

Source : WordNet®

rudimentary
     adj 1: being or involving basic facts or principles; "the
            fundamental laws of the universe"; "a fundamental
            incompatibility between them"; "these rudimentary
            truths"; "underlying principles" [syn: {fundamental},
            {underlying}]
     2: being in the earliest stages of development; "rudimentary
        plans"
     3: not fully developed in mature animals; "rudimentary wings"
        [syn: {vestigial}]