Definitions of security:

• noun:   measures taken as a precaution against theft or espionage or sabotage etc.

  Example: "Military security has been stepped up since the recent uprising"

• noun:   a guarantee that an obligation will be met
• noun:   freedom from anxiety or fear

  Example: "The watch dog gave her a feeling of security"

• noun:   a department responsible for the security of the institution's property and workers

  Example: "The head of security was a former policeman"

• noun:   defense against financial failure; financial independence

  Example: "His pension gave him security in his old age"

• noun:   property that your creditor can claim in case you default on your obligation

  Example: "Bankers are reluctant to lend without good security"

• noun:   a formal declaration that documents a fact of relevance to finance and investment; the holder has a right to receive interest or dividends
• noun:   the state of being free from danger or injury

  Example: "We support the armed services in the name of national security"

• noun:   an electrical device that sets off an alarm when someone tries to break in