The difference between Courtyard and Yard

Courtyard as a noun:

An area, open to the sky, partially or wholly surrounded by walls or buildings.

Yard as a noun:

A small, usually uncultivated area adjoining or (now especially) within the precincts of a house or other building (Wikipedia).

Yard as a noun:

An enclosed area designated for a specific purpose, e.g. on farms, railways etc.

Yard as a noun:

A place where moose or deer herd together in winter for pasture, protection, etc.

Yard as a noun (Jamaica):

One's house or home.

Yard as a verb (transitive):

To confine to a yard.

Yard as a noun:

A unit of length equal to 3 feet in the US customary and British imperial systems of measurement, equal to precisely 0.9144 m since 1959 (US) or 1963 (UK).

Yard as a noun:

Units of similar composition or length in other systems.

Yard as a noun (nautical):

Any spar carried aloft. A long tapered timber hung on a mast to which is bent a sail, and may be further qualified as a square, lateen, or lug yard. The first is hung at right angles to the mast, the latter two hang obliquely.

Yard as a noun (obsolete):

A branch, twig, or shoot.

Yard as a noun (obsolete):

A staff, rod, or stick.

Yard as a noun (obsolete, medical):

A penis.

Yard as a noun (US, slang, uncommon):

100 dollars.

Yard as a noun (obsolete):

The yardland, an obsolete English unit of land roughly understood as 30 acres.

Yard as a noun (obsolete):

The rod, a surveying unit of (once) 15 or (now) 16½ feet.

Yard as a noun (obsolete):

The rood, area bound by a square rod, ¼ acre.

Yard as a noun (finance):

109, A short scale billion; a long scale thousand millions or milliard.