Which term best describes the way this fungus obtains nutrients

Absorption is the best term that would describe on how fungi obtain nutrients from their environment. Fungi, unlike other organisms are not able to ingest or manufacture the food that they want in order to grow. What they do is that they grow through and within a particular material on which they are feeding or absorbing.

Some environments where they can grow are in wood, cheese, soil, and flesh. They absorb the nutrients that they can in order to grow cultures and decompose such organic materials.