Hylomorphism

Hylomorphism (Greek υλο- hylo-, "wood, matter" + -morphism < Greek -μορφη, morph, "form") is a philosophy that highlights the significance of matter in the structure of being, regarding matter as as important (or even more so) as form.

Hylomorphism served as a useful tool in medieval philosophy from (at least) Avicebron to (at least) Thomas Aquinas.