Alter Aeon Online Help

Keywords are:  'encumberance encumbrance'

Encumbrance is a measure of how heavily loaded your character is, and how
hard it is for that character to move.

When your character is carrying its maximum weight, it will have an
encumbrance of 100%, which means it costs twice as much to move as it would
if you were carrying nothing.  If your character is overloaded, it becomes
increasingly more costly to move, and your character may even become unfit
for battle.

It is best to keep your encumbrance low if possible.