Pertaining to or of the nature of substance; being a substance; real; actually existing; true; actual; not seeming or imaginary; not illusive.Having essential value; genuine; sound; sterling.Having firm or good material; strong; stout; solid: as, substantial cloth.Possessed of considerable substance, goods, or estate; moderately wealthy; well-to-do.Real or true in the main or for the most part: as, substantial success.Of considerable amount: as, a substantial gift; substantial profit.Capable of being substantiated or proved.Vital; important.In law, pertaining to or involving the merits or essential right, in contradistinction to questions of form or manner.Pertaining to the substance or tissue of any part or organ.n. That which has a real existence; that which has substance.n. That which has real practical value.n. An essential part.