1. Contracts. The principle that an acceptance becomes effective — and binds the offeror — once it has been properly mailed. • The mailbox rule does not apply, however, if the offer provides that an acceptance is not effective until received. [Cases: Contracts 22(1).C.J.S. Contracts §§ 46–51, 53–54; Trading Stamps and Coupons§§ 7–9.]
2. The principle that when a pleading or other document is filed or served by mail, filing or service is deemed to have occurred on the date of mailing. • The mailbox rule varies from jurisdiction to jurisdiction. For example, it sometimes applies only to certain types of filings, and it may apply when a party uses an overnight courier instead of U.S. mail. — Also termed dispatch rule. [Cases: Habeas Corpus 603; Pleading 40; Process 149; Time
3. C.J.S. Pleading § 109; Process §§ 87–88; Time §§ 2, 4.]
