They actually describe it as "6+1 degrees of freedom" [1] with the gripper being the "+1" - so it's got base, shoulder, elbow, wrist1, wrist2, wrist3, and gripper.
This is a conventional way of describing things. Traditionally robot arms come with a "tool flange" where you attach your own "end effector" (which might be a gripper, or a suction cup, or a welding gun, or a paint sprayer, or whatever) and we count the degrees of freedom before the tool flange separately from those after the tool flange.
Occasionally robots come with 7 degrees of freedom [2] which gives you more options for reaching the same tool flange position. This can be useful in certain applications, like working around obstacles in the environment. It's uncommon though.
so, six variables that produce a posture. 6DoF.
but explaining this makes me feel like i'm missing some deeper meaning in your comment?
This is a conventional way of describing things. Traditionally robot arms come with a "tool flange" where you attach your own "end effector" (which might be a gripper, or a suction cup, or a welding gun, or a paint sprayer, or whatever) and we count the degrees of freedom before the tool flange separately from those after the tool flange.
Occasionally robots come with 7 degrees of freedom [2] which gives you more options for reaching the same tool flange position. This can be useful in certain applications, like working around obstacles in the environment. It's uncommon though.
[1] https://www.seeedstudio.com/reBot-Arm-B601-DM-Bundle.html [2] https://explicit-robotics.github.io/exp_robot/kuka_LBR_iiwa7...