The Collaborative International Dictionary
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.
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.
Douglas Harper's Etymology Dictionary
writ of arrest issued by a court, mid-15c., from Latin capias, literally "thou mayest take," typical first word of such a writ; properly 2nd person singular present subjunctive of capere "to catch, seize, hold" (see capable).