Source : Webster's Revised Unabridged Dictionary (1913)

Penetration \Pen"e*tra`tion\, n. [L. penetratio: cf. F.
   p['e]n['e]tration.]
   1. The act or process of penetrating, piercing, or entering;
      also, the act of mentally penetrating into, or
      comprehending, anything difficult.

            And to each in ward part, With gentle penetration,
            though unseen, Shoots invisible virtue even to the
            deep.                                 --Milton.

            A penetration into the difficulties of algebra.
                                                  --Watts.

   2. Acuteness; insight; sharp discoverment; sagacity; as, a
      person of singular penetration. --Walpole.

   Syn: Discernment; sagacity; acuteness; sharpness;
        discrimination. See {Discernment}, and {Sagacity}.

Source : WordNet®

penetration
     n 1: an attack that penetrates into enemy territory [syn: {incursion}]
     2: clear or deep perception of a situation [syn: {insight}]
     3: the act of entering into or through something; "the
        penetration of upper management by women"
     4: the ability to make way into or through something; "the
        greater penetration of the new projectiles will result in
        greater injuries"
     5: the depth to which something penetrates (especially the
        depth reached by a projectile that hits a target)
     6: the act (by a man) of inserting his penis into the vagina of
        a woman