Final answer:
Cement is the component in mortar that acts as the glue holding masonry together.
Step-by-step explanation:
The component in mortar that acts as the glue that holds CMU, brick, and other types of masonry together is cement. Cement is a fine powder made from a mixture of limestone, clay, and other materials. When mixed with water, cement forms a paste that hardens over time, providing the bonding agent in mortar.
Learn more about Masonry components