Definition of "Vehicle" :

noun: a conveyance that transports people or objects

noun: a medium for the expression or achievement of something

"His editorials provided a vehicle for his political views."

noun: any inanimate object (as a towel or money or clothing or dishes or books or toys etc.) that can transmit infectious agents from one person to another

noun: any substance that facilitates the use of a drug or pigment or other material that is mixed with it