GNU Collaborative International Dictionary of English

Found 2 definitions

1.       
   Mesozoic , a. [Meso- + Gr.  life, fr.  to live.] (Geol.) Belonging, or relating, to the secondary or reptilian age, or the era between the Paleozoic and Cenozoic. See Chart of Geology.
   1913 Webster
         
       

2.       
   Mesozoic, n. The Mesozoic age or formation.
   1913 Webster