This paper studies the geometric design of a robot with five degrees of freedom. According to kinematic synthesis procedure, an industrial robot with five degrees of freedom was used as an example to illustrate the design concept. From the number synthesis point of view, the robot is one freedom less than adequate to perform a general three dimensional motion. The lack of full degree of freedom will restrict the available twist screws for the end‐effector. The unavailable twists of the robot were discovered based on the reciprocal screw system. Singular configurations of the robot were also examined. The dimensional synthesis of a robot is to decide the joint parameters to obtain a good workspace shape and volume. So far, there are no better rules which govern the relations between the joint parameters and the generation of workspace. Under this circumstance, the workspace geometric properties of a robot provide quantitative evaluation of the success of the dimensional synthesis. In this paper, workspace volume and other workspace properties such as the normalized volume index (NV1), volume centroid, and the higher volume moment of inertia are computed. The volume centroid gives the symmetric nature of the workspace, whereas the higher moment reveals the distribution and the compactness of the workspace valume.