The difference between Mole and Quay

Mole as a noun:

A pigmented spot on the skin, a naevus, slightly raised, and sometimes hairy.

Mole as a noun:

Any of several small, burrowing insectivores of the family Talpidae.

Mole as a noun:

Any of the burrowing rodents also called mole rats.

Mole as a noun (espionage):

An internal spy, a person who involves himself or herself with an enemy organisation, especially an intelligence or governmental organisation, to determine and betray its secrets from within.

Mole as a noun:

A kind of self-propelled excavator used to form underground drains, or to clear underground pipelines

Mole as a noun:

A type of underground drain used in farm fields, in which a mole plow creates an unlined channel through clay subsoil.

Mole as a noun (slang, pejorative):

A moll, a bitch, a slut.

Mole as a noun (nautical):

A massive structure, usually of stone, used as a pier, breakwater or junction between places separated by water.

Mole as a noun (rare):

A haven or harbour, protected with such a breakwater.

Mole as a noun (historical):

An Ancient Roman mausoleum.

Mole as a noun (chemistry, physics):

In the International System of Units, the base unit of amount of substance; the amount of substance of a system which contains as many elementary entities (atoms, ions, molecules, etc.) as there are atoms in 0.012 kg of carbon-12. Symbol: mol. The number of atoms is known as Avogadro's number.

Mole as a noun:

A hemorrhagic mass of tissue in the uterus caused by a dead ovum.

Mole as a noun:

One of several spicy sauces typical of the cuisine of Mexico and neighboring Central America, especially the sauce which contains chocolate and which is used in cooking main dishes, not desserts.

Quay as a noun (nautical):

A stone or concrete structure on navigable water used for loading and unloading vessels; a wharf.

Quay as a verb:

To land or tie up at a quay or similar structure, especially used in the phrase "quay up".