wax: any of various substances of either mineral origin or plant or animal origin; they are solid at normal temperatures and insoluble in water
lipid: an oily organic compound insoluble in water but soluble in organic solvents; essential structural component of living cells (along with proteins and carbohydrates)
tracheostomy: a surgical operation that creates an opening into the trachea with a tube inserted to provide a passage for air; performed when the pharynx is obstructed by edema or cancer or other causes