(uncountable) The
quality or
state of being able.
This wood has the ability to fight off insects, fungus, and mold for a considerable time.
(countable) A
skill or competence.
(uncountable, countable) A high level of
skill or competence.
They are persons of ability, who will go far in life.
She has an uncanny ability to defuse conflict.
(uncountable) Suitability or receptiveness to be acted upon.
This phone has the ability to have its software upgraded wirelessly.