Webster's Revised Unabridged Dictionary · 1913

Penetrate

Penetrate , transitive verb

[Latin penetratus, past participle 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.
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. — Shakespeare
The translator of Homer should penetrate himself with a sense of the plainness and directness of Homer's style. — M. Arnold
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.
Things which here were too subtile for us to penetrate. — Ray

Penetrate , intransitive verb

To pass; to make way; to pierce. Also used figuratively.
Preparing to penetrate to the north and west. — J. R. Green
Born where Heaven's influence scarce can penetrate. — Pope
The sweet of life that penetrates so near. — Daniel