The Collaborative International Dictionary of English v.0.48:

Olfactory \Ol*fac"to*ry\, n.; pl. Olfactories.
   An olfactory organ; also, the sense of smell; -- usually in
   the plural.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Olfactory \Ol*fac"to*ry\, a. [L. olfactus, p. p. of olfacere to
   smell; olere to have a smell + facere to make. See Odor,
   and Fact.] (Physiol.)
   Of, pertaining to, or connected with, the sense of smell; as,
   the olfactory nerves; the olfactory cells.
   [1913 Webster]

   Olfactory organ (Anat.), an organ for smelling. In
      vertebrates the olfactory organs are more or less
      complicated sacs, situated in the front part of the head
      and lined with epithelium innervated by the olfactory (or
      first cranial) nerves, and sensitive to odoriferous
      particles conveyed to it in the air or in water.
      [1913 Webster]

WordNet (r) 3.0 (2006):

olfactory
    adj 1: of or relating to olfaction [syn: olfactory,
           olfactive]