Source : Webster's Revised Unabridged Dictionary (1913)

Internal \In*tern"al\, a. [L. internus; akin to interior. See
   {Interior}.]
   1. Inward; interior; being within any limit or surface;
      inclosed; -- opposed to {external}; as, the internal parts
      of a body, or of the earth.

   2. Derived from, or dependent on, the thing itself; inherent;
      as, the internal evidence of the divine origin of the
      Scriptures.

   3. Pertaining to its own affairs or interests; especially,
      (said of a country) domestic, as opposed to {foreign}; as,
      internal trade; internal troubles or war.

   4. Pertaining to the inner being or the heart; spiritual.

            With our Savior, internal purity is everything.
                                                  --Paley.

   5. Intrinsic; inherent; real. [R.]

            The internal rectitude of our actions in the sight
            of God.                               --Rogers.

Source : WordNet®

internal
     adj 1: happening or arising or located within some limits or
            especially surface; "internal organs"; "internal
            mechanism of a toy"; "internal party maneuvering"
            [ant: {external}]
     2: occurring within an institution or community; "intragroup
        squabbling within the corporation" [syn: {intragroup}]
     3: inside the country; "the British Home Office has broader
        responsibilities than the United States Department of the
        Interior"; "the nation's internal politics" [syn: {home(a)},
         {interior(a)}, {national}]
     4: located inward; "Beethoven's manuscript looks like a bloody
        record of a tremendous inner battle"- Leonard Bernstein;
        "she thinks she has no soul, no interior life, but the
        truth is that she has no access to it"- David Denby; "an
        internal sense of rightousness"- A.R.Gurney,Jr. [syn: {inner},
         {interior}]
     5: innermost or essential; "the inner logic of Cubism"; "the
        internal contradictions of the theory"; "the intimate
        structure of matter" [syn: {inner}, {intimate}]