gluten-free diet: diet prescribed to treat celiac disease; eliminates such foods as wheat and rye and oats and beans and cabbage and turnips and cucumbers that are rich in gluten
substance: a particular kind or species of matter with uniform properties
sclerotium: compact usually dark-colored mass of hardened mycelium constituting a vegetative food-storage body in various true fungi; detaches when mature and can give rise to new growth