noun The process of becoming older or more mature.
noun The deliberate process of making something (such as an antique) appear (or, in science fiction, become) older than it is.
noun The accumulation of damage to macromolecules, cells, tissues and organs with the passage of time; the progressing loss of health, mobility, vibrancy and body functionality, resulting in biological death.
noun Wear; wear and tear.
adjective Becoming elderly.
The aging artist could no longer steadily hold the brush.