What is the liquid part of the blood called?

Blood plasma is the watery, liquid component of blood. When separated from the rest of the blood, plasma is a light yellow liquid. 

The main role of plasma is to supply nutrients, hormones, and proteins to the different parts of the body when in need. It comprises of red blood cells, white blood cells, and platelets. 

Within plasma, there are many important dissolved substances, like proteins, electrolytes, nutrients, gases, and waste products.