When a carrier protein facilitates the movement of two molecules across the membrane in same direction, it is called 

Symport is a type of membrane transport where a carrier protein facilitates the movement of two molecules or ions across the membrane in the same direction. 
(1) Uniport is a type of membrane transport where a carrier protein facilitates the movement of a single molecule or ion across the membrane in one direction. 
(2) Transport is a general term that refers to the movement of substances across a membrane. 
(3) Antiport is a type of membrane transport where a carrier protein facilitates the movement of two molecules or ions across the membrane in opposite directions.