What is the cement between bricks called?
Cement is used in grout, mortar and concrete as a binder, that “glues” other ingredients (or just itself) together to give a solid mass of material. The most common cement by far is Portland cement in the construction industry.
The material between bricks is called “mortar”.
The various joints have names too.
The horizontal joint between successive “courses” is called a “bed” joint.
The vertical joint at the end of a brick is a “perpend” or “head” joint.
In solid masonry, where multiple “wythes” of bricks are combined to give an element thicker than one brick, the vertical joint between the wythes is called a “collar” joint.