Security is protection from, or resilience against, potential harm (or other unwanted coercion). Beneficiaries (technically referents) of security may be persons and social groups, objects and institutions, ecosystems, or any other entity or phenomenon vulnerable to unwanted change.
Security mostly refers to protection from hostile forces, but it has a wide range of other senses: for example, as the absence of harm (e.g., freedom from want); as the presence of an essential good (e.g., food security); as resilience against potential damage or harm (e.g. secure foundations); as secrecy (e.g., a secure telephone line); as containment (e.g., a secure room or cell); and as a state of mind (e.g., emotional security).
Security is both a feeling and a state of reality. One can feel secure, while they aren't, but also feel insecure while they are secure. This distinction is usually not very clear to express in the English language.
The term is also used to refer to acts and systems whose purpose may be to provide security (security company, security police, security forces, security service, security agency, security guard, cyber security systems, security cameras, remote guarding). Security can be physical and virtual.
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