What is Capias?

Legal Definition
Practice. This word, the signification of which is " that you take," is applicable to many heads of practice. Several writs and processes, commanding the sheriff to take the person of the defendant, are known by the name of capias. For example: there are writs of capias ad respondendum, writs of capias ad computandum, writs of capias ad satisfaciendum, &c., each especially adapted to the purposes indicated by the words used for its designation. See 3 Bl. Com. 281; 3 Bouv. Inst. n. 2794.
-- Bouviers Law Dictionary
Legal Definition
Lat. "That you take." The general name for several species of writs, the common characteristic of which is that they require the officer to take the body of the defendant into custody; they are writs of attachment or arrest. In English practice. A capias is the process on an indictment when the person charged is not in custody, and in cases not otherwise provided for by statute. 4 Steph. Comm. 383.
-- Black's Law Dictionary
Legal Definition
A writ for the seizure of the property or person of the defendant.
-- Ballentine's Law Dictionary