carrier

noun

• 1a person or thing that carries, holds, or conveys something:water carriers
• British a carrier bag:a plastic carrier

• 2a person or company that undertakes the professional conveyance of goods or people:the instruments can be sent by carrier
• a vessel or vehicle for transporting goods in bulk: the largest timber carrier ever to dock at Sharpness
• an aircraft carrier: aircraft from the carrier Illustrious attacked the Italian fleet
• a company that provides facilities for conveying telecommunications messages: Japan’s biggest international telecoms carrier is Singapore Telecom

• 3a person or animal that transmits a disease-causing organism to others, especially without suffering from it themselves:the badger is a carrier of bovine tuberculosis
• an individual that possesses a particular gene, especially as a single copy whose effect is masked by a dominant allele, so that the associated characteristic (such as a hereditary disease) is not displayed but may be passed to offspring: the husband and wife may both be carriers of the same recessive gene, with a 25% chance of a diseased child

• 4a substance used to support or convey another substance such as a pigment, catalyst, or radioactive material.
• Physicsshort for charge carrier.
• Biochemistry a molecule that transfers a specified molecule or ion within the body, especially across a cell membrane.