The Collaborative International Dictionary of English v.0.48:

Ratitae \Ra*ti"tae\ (r[.a]*t[imac]"t[-e]), n. pl. [NL., fr. L.
   ratis a raft; cf. L. ratitus marked with the figure of a
   raft.] (Zool.)
   An order of birds in which the wings are small, rudimentary,
   or absent, and the breastbone is destitute of a keel. The
   ostrich, emu, moa, and apteryx are examples.
   [1913 Webster]

WordNet (r) 3.0 (2006):

Ratitae
    n 1: used in former classifications to include all ratite bird
         orders [syn: Ratitae, superorder Ratitae]