Final answer:
The stem 'myco' in the word mycosis signifies 'fungus' or 'fungal,' used when referring to fungal infections and other fungus-related terms like mycelium and mycorrhizal.
Step-by-step explanation:
The stem 'myco' in the word mycosis means 'fungus' or 'fungal.' The term mycosis specifically refers to a fungal infection. This is in line with other terms that also begin with 'myco,' such as mycelium, which is the vegetative network of branched, tubular hyphae that make up the majority of a fungus's mass. Mycorrhizal associations, which involve a mutualistic relationship between fungi and vascular plant roots, also contain 'myco' to signify the fungal component of the relationship.