Common carrier refers to a person or entity in the business of transporting goods or people for hire, as a public service. A private carrier, in contrast, is employed to transport good for people for specific needs on an individual case basis. For example, city buses are a common carrier, as opposed to a private carrier such as a moving company which is hired on a one-time basis. A common carrier runs according to a regular schedule on a designated route.

Under common law rules, a common carrier is generally liable for all losses which may occur to property entrusted to his charge in the course of business, unless he can prove the loss happened in consequence of the act of God, or of the enemies of the United States, or by the act of the owner of the property.