Dictionary.net

To procure the release of a person from legal custody, by undertaking that he shall appear at the time and place designated and submit himself to the jurisdiction and judgment of the court To set at liberty a person arrested or imprisoned, on security being taken for his appearance on a day and a place certain, which security is called “bail,” because the party arrested or imprisoned is delivered into the hands of those who bind themselves for his forthcoming, (that is, become bail for his due appearance when required,) in order that he may be safely protected from prison. Wharton. Stafford v. State, 10 Tex. App. 49.