penetration

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun The act or process of piercing or penetrating something, especially.
• noun The act of entering a country or organization so as to establish influence or gain information.
• noun An attack that penetrates enemy territory or a military front.
• noun Insertion of the penis into the vagina or anus.
• noun The power or ability to penetrate.
• noun The depth reached by a projectile after hitting its target.
• noun The degree to which a commodity, for example, is sold or recognized in a particular market.
• noun The extent of influence that one culture or nation has on another.
• noun The capacity or action of understanding; insight.

from The Century Dictionary.

• noun The act of penetrating or piercing.
• noun Power of penetrating; specifically, in gunnery, the depth a projectile will pass into any material against which it is fired.
• noun Mental acuteness; discernment; insight: as, a man of extraordinary penetration.
• noun In optics: Of a microscope objective, its power of giving fairly distinct vision for points both inside and outside of its exact focus.
• noun Of a telescope, its space-penetrating power, as Herschel called it—i. e. the number of times by which the distance of an observed star might be increased while still appearing of the same brightness in the telescope as it does to the naked eye. It is proportional to the square root of the illuminating power, and for an achromatic telescope is approximately equal to four times its aperture in inches.

from the GNU version of the Collaborative International Dictionary of English.

• noun The act or process of penetrating, piercing, or entering; also, the act of mentally penetrating into, or comprehending, anything difficult.
• noun Acuteness; insight; sharp discoverment; sagacity.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun the ability to make way into or through something
• noun the depth to which something penetrates (especially the depth reached by a projectile that hits a target)
• noun clear or deep perception of a situation
• noun the act of entering into or through something
• noun an attack that penetrates into enemy territory
• noun the act (by a man) of inserting his penis into the vagina of a woman