pre·ser·va·tive /prɪˈzɝvətɪv/ 名詞
Pre·serv·a·tive a. Having the power or quality of preserving; tending to preserve, or to keep from injury, decay, etc.
Pre·serv·a·tive, n. That which preserves, or has the power of preserving; a presevative agent.
To wear tablets as preservatives against the plague. --Bacon.
adj : tending or having the power to preserve; "the timbers should
be treated with a preservative"
n : a chemical compound that is added to protect against decay