Explanation (noun)

1. A statement or account that makes something clear or easy to understand.
2. A reason or justification for a particular action or decision.
3. The act or process of explaining.

Origin:

From the latin explānātiōn-em, from explānāre, meaning to make plain.

Examples:

1. He provided an explanation for his absence.
2. The teacher gave a detailed explanation of the new math problem.
3. The explanation of the experiment was not clear.
4. The company's CEO gave an explanation for the layoff.
5. The explanation of the law is given in the book.