Essence; the material or necessary component of something.
A matter of substance, as distinguished from a matter of form, with respect to pleadings, affidavits, indictments, and other legal instruments, entails the essential sufficiency, validity, or merits of the instrument, as opposed to its method or style.
SUBSTANCE, evidence. That which is essential; it is used in opposition to
form.
2. It is a general rule, that on any issue it is sufficient to prove
the substance of the issue. For example, in a case where the defendant
pleaded payment of the principal sum and all interest due, and it appeared
in evidence that a gross sum was paid, not amounting to the full interest,
but accepted by the plaintiff as full payment, the proof was held to be
sufficient. 2 Str. 690; 1 Phil. Ev. 161.