Portability is usually the ease with which you can move your chair around and this depends largely on what the chair is made out of.For instance, chairs made out of wood or steel are heavier and hence less portable than a chair made from aluminium.
Chairs that are collapsible and foldable are also one of the easiest to carry around.
And lastly, the presence of a shoulder strap is usually an indication that that chair is very portable.