safe·guard 
(sāfgärd′)
(sāfgärd′)n.
Something that provides protection against attack, loss, or injury, as:
a. A precautionary measure: The doctor prescribed antibiotics as a safeguard against infection.
b. A mechanical device designed to prevent accidents or injury.
c. A protective stipulation, as in a contract.
d. A safe-conduct.
tr.v. safe·guard·ed, safe·guard·ing, safe·guards
To ensure the safety or integrity of; protect or preserve: a strategy to safeguard the country from attack; investments that can help safeguard one's savings. See Synonyms at defend.