\Ep`i*ster"num\, n.; pl. {Episterna}. [NL. See
{Epi-}, and {Sternum}.]
1. (Anat.)
   (a) A median bone connected with the sternum, in many
       vertebrates; the interclavicle.
   (b) Same as {Epiplastron}.

2. (Zo["o]l.) One of the lateral pieces next to the sternum
   in the thorax of insects.