1. <genetics, microbiology> An individual who does not display the symptoms of a disease, but harbors the pathogen which causes it, or has the gene (or genes) for it, and can transmit the disease to others either through interacting with other individuals, or by passing the disease-causing gene (or genes) to offspring.

2. <pharmacology> A substance which transports things, such as a carrier protein.

(09 Oct 1997)