Definition
Security is a condition in which the risk of undesirable events has been reduced to a level considered acceptable through appropriate organisational, technical or procedural measures.
Human Explanation
Security does not mean the complete absence of threats. It means being able to protect people, information, assets and processes from undesirable consequences.
Why it Matters
Eliminating all risk is impossible. The purpose of security is to manage risk deliberately and reduce its consequences.
Conceptual Boundary
Security is not a product or a single technical solution. It is a property of the complete system that results from how the system is designed, used and managed.
Practical Perspective
Most incidents do not result from one error or one vulnerability but from a combination of several apparently minor weaknesses across the system.