lipoid n an oily organic compound insoluble in water but soluble in organic solvents; essential structural component of living cells (along with proteins and carbohydrates) Usage(s) The electrical charge accumulates on the lipoid film, breaks through, and thereby establishes electric balance between the two fluids. On their way from the nose and throat they may carry infections causing what is called lipoid (fatty) pneumonia. Synonym(s) lipid lipide