The Collaborative International Dictionary of English v.0.48:

Foliaceous \Fo`li*a"ceous\, a. [L. foliaceus, fr. folium leaf.]
   1. (Bot.) Belonging to, or having the texture or nature of, a
      leaf; having leaves intermixed with flowers; as, a
      foliaceous spike.
      [1913 Webster]

   2. (Min.) Consisting of leaves or thin lamin[ae]; having the
      form of a leaf or plate; as, foliaceous spar.
      [1913 Webster]

   3. (Zool.) Leaflike in form or mode of growth; as, a
      foliaceous coral.
      [1913 Webster]

WordNet (r) 3.0 (2006):

foliaceous
    adj 1: of or pertaining to or resembling the leaf of a plant
    2: bearing numerous leaves [syn: foliaceous, foliose,
       foliaged]
    3: (especially of metamorphic rock) having thin leaflike layers
       or strata [syn: foliate, foliated, foliaceous]