Definitions
Broadband
Penetration is the number or percentage of broadband subscribers per capita or per household.
Security
Penetration is "the unauthorized act of bypassing the security mechanisms of a cryptographic system."[1]
Society
Penetration is "the degree to which a technology has been adopted by a community."[2]
Overview (Broadband)
Penetration is "normally calculated by dividing the number of subscribers to a particular service by the population and multiplying by 100."[3]