pen ‧ e ‧ tra ‧ tion /ˌpenəˈtreɪʃ ə n, ˌpenɪˈtreɪʃ ə n/ BrE AmE noun
1 . [uncountable and countable] when something or someone enters or passes through something, especially when this is difficult:
Cover the entire device to prevent water penetration.
penetration of
The attack failed to lead to any deep penetration of enemy territory.
2 . [uncountable and countable] the degree to which a product is available or sold in an area
penetration of
the rise in import penetration of the domestic market
3 . [uncountable] when a system of beliefs enters a society and becomes accepted
penetration of
the penetration of Marxism into Latin America
4 . [uncountable] when someone joins and gets accepted by an organization, business etc in order to find out secret information
penetration of
foreign penetration of the British secret service
5 . [uncountable] when a man puts his ↑ penis into a woman’s ↑ vagina or into someone’s ↑ anus
6 . [uncountable] a special ability to understand things very clearly and completely