NOUN (1)

1. a chemical compound that is added to protect against decay or decomposition;


ADJECTIVE (1)

1. tending or having the power to preserve;
- Example: "timbers should be treated with a preservative substance"

The Collaborative International Dictionary of English v.0.48:

Preservative \Pre*serv"a*tive\, a. [Cf. F. pr['e]servatif.]
   Having the power or quality of preserving; tending to
   preserve, or to keep from injury, decay, etc.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Preservative \Pre*serv"a*tive\, n.
   That which preserves, or has the power of preserving; a
   presevative agent.
   [1913 Webster]

         To wear tablets as preservatives against the plague.
                                                  --Bacon.
   [1913 Webster]

WordNet (r) 3.0 (2006):

preservative
    adj 1: tending or having the power to preserve; "timbers should
           be treated with a preservative substance"
    n 1: a chemical compound that is added to protect against decay
         or decomposition

Moby Thesaurus II by Grady Ward, 1.0:

28 Moby Thesaurus words for "preservative":
   backward, brine, conservational, conservationist, conservative,
   conservatory, conserving, die-hard, embalming fluid, fogyish,
   formaldehyde, keeping, nonprogressive, old-fashioned, old-fogyish,
   old-line, opposed to change, preservative medium, preservatory,
   preserving, protective, right-wing, salt, saving, standpat,
   ultraconservative, unprogressive, vinegar