to enter into; to make way into the interior of; to effect an entrance into; to pierce; as, light penetrates darkness.-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.-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.-to pass; to make way; to pierce. also used figuratively.