The Collaborative International Dictionary of English v.0.48:

Capias \Ca"pi*as\, n. [L. thou mayst take.] (Low)
   A writ or process commanding the officer to take the body of
   the person named in it, that is, to arrest him; -- also
   called writ of capias.
   [1913 Webster]

   Note: One principal kind of capias is a writ by which actions
         at law are frequently commenced; another is a writ of
         execution issued after judgment to satisfy damages
         recovered; a capias in criminal law is the process to
         take a person charged on an indictment, when he is not
         in custody. --Burrill. Wharton.
         [1913 Webster]