It's poser shorthand :-) In theory: A "Pose" moves the body parts of the figure. (Poses can be saved with or without morph channels, but can't be saved with material settings: you have to create material poses manually.) Partial poses affect only specified body parts. A MAT (material) Pose changes the material settings without affecting the pose or morph channels. Sub-dividing MAT poses change the material settings only on specified body parts (eg to put stockings on a character without changing the main body or face texture). A MOR (morph) pose changes the morph channels without (if it's created correctly) affecting the pose. ...and all of the above should come as .pz2 files and "live" in the Poses library.