Security is protection from danger, harm, or loss. When you feel secure, you're safe from things that could hurt you or take away what matters to you. A house with good security might have strong locks on the doors and windows that keep intruders out. A computer with good security has passwords and software that protect your personal information from hackers.

Security comes in many forms. Physical security protects buildings, objects, and people: think of security guards patrolling a museum to protect valuable artwork, or a seatbelt providing security in a car. Financial security means having enough money saved that you don't have to worry about paying for necessities. When someone talks about job security, they mean confidence that they won't suddenly lose their job.

Nations maintain security too. National security involves protecting a country and its citizens from threats like invasion or terrorism. The word security in this context often appears in phrases like “national security agency” or “security clearance,” which is special permission to access secret information.

Sometimes security requires trade-offs. Airport security checks can be inconvenient, but they help keep travelers safe. Online security might mean remembering complicated passwords, but that protects your accounts from strangers. The challenge is finding the right balance: enough security to feel safe without making life unnecessarily difficult or unfair.