The ability of a particular radio frequency to pass through non-metallic materials.

Low-frequency systems have better penetration than UHF systems.

1. The invasion, intrusion, perforation, or stabbing of something: The archery instructor told Fred that the heavier the arrow is, the greater its penetration into the target.
2. Insight, perception, discernment, cleverness, or astuteness: Patricia had a talent for making penetrations when analyzing psychological situations.
3. The action or process of getting through or into something: Some flowers grow in forest areas where there are strong penetrations of sunshine.
4. The degree to which a product is recognized and purchased by users in a particular market: The vocabulary software has attained a high degree of market penetration; especially, by educators and students.
5. The recruitment of agents within, or the infiltration of agents or monitoring devices into, enemy organizations in order to gather information: There are those nations that are constantly making penetrations into the military establishments of other countries in order to learn about their secret plans and activities, their military data, their weapon designs, etc.

A record of the velocity with which a drill cuts a bore or a hole, including such factors as the hole sizes, bit sizes, mud pressures, rotation speeds, and the forces on the bits: The penetration logs are used to determine the thickness of coal and dirt bands in deep holes.

The selling of a new product at a lower price in order to lure customers away from some other established product: The company was using penetration pricing for its new computer, with very similar operational procedures, at a much lower level than the other company so people would become interested in trying it out.

The actual speed of boring holes with drilling tools: The penetration rates of the drills were recorded for future evaluations.

The degree or depth to which the heating of a medical treatment is likely to extend: Dr. Simmons was trying to determine how long and to what degree the thermotherapeutic penetrations should be applied to Mrs. Johnson, her patient.