What is Special Bail?

Legal Definition
A person who becomes specially bound to answer for the appearance of another; the recoguizance or act by which such person thus becomes bound, is also called special bail. Vide Bail.
-- Bouviers Law Dictionary
Legal Definition
In practice. Persons who undertake jointly and severally in behalf of a defendant arrested on mesne process in a civil action that, if he be condemned in the action, he shall pay the costs and condemnation, (that is, the amount which may be recovered against him,) or render himself a prisoner, or that they will pay it for him. 3 Bl. Comm. 291; 1 Tidd, Pr. 245.
-- Black's Law Dictionary
Legal Definition
Bail taken in a civil action.
-- Ballentine's Law Dictionary