n.1. One that transports or conveys: baggage carriers; a message carrier.
2. One, such as a person, business, or organization, that deals in the transport of passengers or goods.
3. A mechanism or device by which something is conveyed or conducted.
4. Medicine A person or animal that shows no symptoms of a disease but harbors the infectious agent of that disease and is capable of transmitting it to others.
5. Genetics An individual that carries one gene for a particular recessive trait. A carrier does not express the trait but, when mated with another carrier, can produce offspring that do.
6. Physics A boson, especially a gauge boson, that conveys a force or mediates an interaction between subatomic particles.
7. Electronics a. A carrier wave.
b. A charge-carrying entity, especially an electron or a hole in a semiconductor.
8. An aircraft carrier.
9. An insurance or underwriting organization.
10. A telecommunications company.