PSA: It's fine and recommended to use the term "mushroom" to mean "mushroom". Don't use "fungus" when you're referring only to the fruit body because it would be wrong. The term "fungus" is normally used to refer to a whole organism* or a whole species/group of fungi.
*The notion of an organism in fungi is a bit special because the mycelium can freely be broken into isolated patches - but mushrooms are formed by many strands of mycelium (hyphae) from the same organism/strain getting together and making a beautiful mushroom with a single genome. Mushrooms are not chimeras, normally in most species (for what I know). However, if you mix multiple "individuals" i.e. mycelium from the same species with different genes, it's war. This can be observed on agar plates when growing mycelium from many spores that germinate and mate, resulting in different diploid patches that won't overlap and will slow each other's growth.
