The quality or state of being substantial; having substance or material existence. The substantiality of the evidence presented in court was enough to convince the jury of the defendant's guilt.
The quality of being important, valid, or significant. The substantiality of her contributions to the project was recognized by all her colleagues.
In philosophy, that which has independent existence; substance or essence as distinguished from its attributes. Many scholastic debates revolved around the substantiality of the soul.