What is Variableness?

Variableness definition and meaning on Dictionary terms:

apt or liable to vary or change; changeable: variable weather; variable moods.
capable of being varied or changed; alterable: a variable time limit for completion of a book.
inconstant; fickle: a variable lover.
having much variation or diversity.
Biology. deviating from the usual type, as a species or a specific character.
Astronomy. (of a star) changing in brightness.
Meteorology. (of wind) tending to change in direction.
Mathematics. having the nature or characteristics of a variable.