What do the terms hydrophilic and hydrophobic mean and how do they relate to the structure of a cell membrane

Hydrophilic:

Molecules forming ionic or hydrogen bonds with the water molecule. (Attracted to water)

Hydrophobic:

Nonpolar molecules that repel the water molecules.                                                (Repelled by water)

How these relate to the structure of a cell membrane:

Hydrophilic and Hydrophobic are components of Phospholipids. Phospholipids are one of the principal components of the plasma membrane.