Course: A course is a horizontal layer of bricks or stones. 
    Header: It is a brick or stone which lies with its greatest length at right angles to the face of the work. In case of stone masonry header is sometimes known as through stone. The course of brick work in which all the bricks are laid as headers is known as header course. 
    Stretcher: It is a brick or a stone which lies with its longest side parallel to the face of the work. The course of brick work in which all the bricks are laid as stretchers is known as stretcher course. 
    Arrises: The edges formed by the intersection of plane surface of brick are called the arrises and they should be sharp, square and free from damage.