Matter
Hegel (Logic of Essence) / (philosophy of nature)
In the relation form/matter (Ch. 6.6), matter is the undetermined substrate that is determined through form. It is the "totality of properties" (Ch. 5.11), but still without unity. In the philosophy of nature, matter is the first realization of objectivity (Ch. 29.1).
Origin
Form; Content; Thing; Substance; Nature
In Hegel
Enc. §133 (Logic); Enc. §261 (Nature)