noun, plural: phospholipids
Phospholipids are amphipathic compounds in a way that the 'head' is hydrophilic and the lipophilic 'tail' is hydrophobic. They serve as a major structural component of most biological membranes. They form the lipid bilayer in cell membranes of organisms.
Word origin: phosphor- » from phosphorus + -lipid » from Greek lipos, fat.