The Collaborative International Dictionary of English v.0.48:

Penetrate \Pen"e*trate\, v. i.
   To pass; to make way; to pierce. Also used figuratively.
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         Preparing to penetrate to the north and west. --J. R.
                                                  Green.
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         Born where Heaven's influence scarce can penetrate.
                                                  --Pope.
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         The sweet of life that penetrates so near. --Daniel.
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The Collaborative International Dictionary of English v.0.48:

Penetrate \Pen"e*trate\, v. t. [imp. & p. p. Penetrated; p.
   pr. & vb. n. Penetrating.] [L. penetratus, p. p. of
   penetrare to penetrate; akin to penitus inward, inwardly, and
   perh. to pens with, in the power of, penus store of food,
   innermost part of a temple.]
   1. To enter into; to make way into the interior of; to effect
      an entrance into; to pierce; as, light penetrates
      darkness.
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   2. To affect profoundly through the senses or feelings; to
      touch with feeling; to make sensible; to move deeply; as,
      to penetrate one's heart with pity. --Shak.
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            The translator of Homer should penetrate himself
            with a sense of the plainness and directness of
            Homer's style.                        --M. Arnold.
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   3. To pierce into by the mind; to arrive at the inner
      contents or meaning of, as of a mysterious or difficult
      subject; to comprehend; to understand.
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            Things which here were too subtile for us to
            penetrate.                            --Ray.
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WordNet (r) 3.0 (2006):

penetrate
    v 1: pass into or through, often by overcoming resistance; "The
         bullet penetrated her chest" [syn: penetrate,
         perforate]
    2: come to understand [syn: penetrate, fathom, bottom]
    3: become clear or enter one's consciousness or emotions; "It
       dawned on him that she had betrayed him"; "she was penetrated
       with sorrow" [syn: click, get through, dawn, come
       home, get across, sink in, penetrate, fall into
       place]
    4: enter a group or organization in order to spy on the members;
       "The student organization was infiltrated by a traitor" [syn:
       infiltrate, penetrate]
    5: make one's way deeper into or through; "The hikers did not
       manage to penetrate the dense forest"
    6: insert the penis into the vagina or anus of; "Did the
       molester penetrate the child?"
    7: spread or diffuse through; "An atmosphere of distrust has
       permeated this administration"; "music penetrated the entire
       building"; "His campaign was riddled with accusations and
       personal attacks" [syn: permeate, pervade, penetrate,
       interpenetrate, diffuse, imbue, riddle]