ve·hi·cle 
(vēĭ-kəl)
(vēĭ-kəl)n.
1.
a. A device or structure for transporting persons or things; a conveyance: a space vehicle.
b. A self-propelled conveyance that runs on tires; a motor vehicle.
2. A medium through which something is transmitted, expressed, or accomplished: His novels are a vehicle for his political views.
3. The concrete or specific word or phrase that is applied to the tenor of a metaphor and gives the metaphor its figurative power, as walking shadow in "Life's but a walking shadow" (Shakespeare).
4. A play, role, or piece of music used to display the special talents of one performer or company.
5. An inactive substance that is combined with an active medication to facilitate administration.
6. A substance, such as oil, in which paint pigments are mixed for application.
[Latin vehiculum, from vehere, to carry; see wegh- in the Appendix of Indo-European roots.]