A solid strut is a strut that has a uniform cross-section along its entire length. It is a continuous member that does not have any breaks or openings along its length. Solid struts are commonly used in applications where high stiffness and strength are required.

A slotted strut, on the other hand, is a strut that has one or more longitudinal slots or openings along its length. These slots can help to reduce the weight of the strut while maintaining its overall strength and stiffness. Slotted struts are commonly used in applications where weight is a critical factor, such as in aerospace or automotive engineering.