Molecular function

GO:0005478

Enables the directed movement of substances (such as macromolecules, small molecules, ions) into, out of or within a cell, accross or in between cells.

carrier

Some transporters, such as certain members of the SLC family, are referred to as 'carriers'; however GO uses carrier with a different meaning: a carrier binds to and transports the substance (see GO:0140104 molecular carrier activity), whereas a transporter forms some pore that allows the passing of molecules.