penetration

As a noun penetration

is penetration.

As an adjective undefined is

lacking a definition or value.

As nouns the difference between penetration and intrusion

is that penetration is penetration while intrusion is intrusion.

As nouns the difference between stick and penetration

is that stick is (ireland) a member of the official ira while penetration is penetration.

As a proper noun stick

is (musici) the chapman stick, an electric musical instrument devised by emmett chapman.

As nouns the difference between permeant and penetration

is that permeant is (biochemistry) a substance which is able to pass through or into a membrane or polymer while penetration is penetration.

As an adjective permeant

is (biochemistry) able to pass through or into a given semipermeable membrane or polymer.

Estimate is a related term of penetration.

As nouns the difference between estimate and penetration

is that estimate is a rough calculation or guess while penetration is penetration.

As a verb estimate

is to calculate roughly, often from imperfect data.