[1] : The Collaborative International Dictionary of English v.0.48

cretacic \cretac"ic\
   webster 1913 suppl. +pjc

   cretaceous acid,
   an old name for carbonic acid.

   cretaceous formation geol., the series of strata of
      various kinds, including beds of chalk, green sand, etc.,
      formed in the cretaceous period; -- called also the chalk
      formation. see the diagram under geology.

   cretaceous period geol., the time in the latter part of
      the mesozoic age during which the cretaceous formation was
      deposited, and at the end of which the dinosaurs died out.
      see cretaceous.
      1913 webster +pjc
see also:
cretaceous acid cretaceous formation chalk formation geology cretaceous period cretaceous 

[2] : WordNet (r) 2.0

cretaceous period
     n : from 135 million to 63 million years ago; end of the age of
         reptiles; appearance of modern insects and flowering
         plants syn: cretaceous
see also:
cretaceous 

Period >> P Words
Period, definition of term: Period
period_pag1.html

Cretaceous >> C Words
Cretaceous, definition of term: Cretaceous
cretaceous_pag1.html

Time Period >> T Words
Time Period, definition of term: Time Period
time+period_pag1.html

Jurassic Period >> J Words
Jurassic Period, definition of term: Jurassic Period
jurassic+period_pag1.html