The difference between Compound and Pen

Compound as a noun:

an enclosure within which workers, prisoners, or soldiers are confined

Compound as a noun:

a group of buildings situated close together, e.g. for a school or block of offices

Compound as an adjective:

composed of elements; not simple

Compound as an adjective (music):

An octave higher than originally (i.e. a compound major second is equivalent to a major ninth).

Compound as a noun:

Anything made by combining several things.

Compound as a noun (chemistry, dated):

A substance made from any combination elements.

Compound as a noun (chemistry):

A substance formed by chemical union of two or more ingredients in definite proportions by weight.

Compound as a noun (linguistics):

A lexeme that consists of more than one stem; compound word; for example , formed from and .

Compound as a noun (rail):

a , a steam locomotive with both high-pressure and low-pressure cylinders.

Compound as a verb (transitive):

To form (a resulting mixture) by combining different elements, ingredients, or parts.

Compound as a verb (transitive):

To assemble (ingredients) into a whole; to combine, mix, or unite.

Compound as a verb (transitive):

To modify or change by combination with some other thing or part; to mingle with something else.

Compound as a verb (transitive, legal):

To settle by agreeing on less than the claim, or on different terms than those stipulated.

Compound as a verb (transitive):

To settle amicably; to adjust by agreement; to compromise.

Compound as a verb (intransitive):

To come to terms of agreement; to agree; to settle by a compromise; usually followed by with before the person participating, and for before the thing compounded or the consideration.

Compound as a verb (transitive, obsolete):

To compose; to constitute.

Compound as a verb (intransitive, finance):

To increase in value with interest, where the interest is earned on both the principal sum and prior earned interest.

Compound as a verb (transitive):

To worsen a situation

Pen as a noun:

An enclosed area used to contain domesticated animals, especially sheep or cattle.

Pen as a noun (slang):

A prison cell.

Pen as a noun (baseball):

The bullpen.

Pen as a verb (transitive):

To enclose in a pen.

Pen as a noun:

A tool, originally made from a feather but now usually a small tubular instrument, containing ink used to write or make marks.

Pen as a noun (figurative):

A writer, or his style.

Pen as a noun (colloquial):

Marks of ink left by a pen.

Pen as a noun:

A light pen.

Pen as a noun (zoology):

The internal cartilage skeleton of a squid, shaped like a pen.

Pen as a noun (now, rare, poetic, dialectal):

A feather, especially one of the flight feathers of a bird, angel etc.

Pen as a noun (poetic):

A wing.

Pen as a verb (transitive):

To write (an article, a book, etc.).

Pen as a noun:

A female swan.

Pen as a noun (soccer, slang):

penalty