The term "Order Hymenogastrales" refers to a classification of fungi within the Basidiomycota phylum. This order is known for its mushrooms with a belly-like shape, with the hymenium (the layer that produces spores) located on the underside of the cap. Some synonyms for this order include the "bellybutton fungi" and the "omphalotoid fungi". Additionally, the term "omphalotus" is often used to refer to species within this order, such as Omphalotus olearius, which is commonly known as the "Jack-O-Lantern mushroom". With the wide variety of species in this order, it's important to use specific scientific names to accurately categorize and identify these fungi.