Main"prise (?), n. [F. main hand + prise a taking, fr. prendre, p. p. pris to take, fr. L. prehendere, prehensum.] (Law) (a) A writ directed to the sheriff, commanding him to take sureties, called mainpernors, for the prisoner's appearance, and to let him go at large. This writ is now obsolete. Wharton. (b) Deliverance of a prisoner on security for his appearance at a day.

Main"prise, v. t. [imp. & p. p. Mainprised (?); p. pr. & vb. n. Mainprising.] (Law) To suffer to go at large, on his finding sureties, or mainpernors, for his appearance at a day; -- said of a prisoner.