Proportion (noun)

1. The relationship in terms of quantity, size, or number between two or more things.
2. The relative size, amount, or degree of something, especially when compared to others.
3. The appropriate relationship in size, amount, or degree between different parts of something.
4. A part or share, especially of a total.
5. A ratio of one part of a quantity to another part, usually expressed as a fraction.

Origin:

Late middle english from old french proporcion, from latin proportionem (nominative proportio) meaning a proportion, a due relation, from pro- meaning forward, for + portio meaning a part.

Examples:

1. The proportion of water to flour in the recipe is critical.
2. The proportion of the population living in poverty has increased.
3. The house is designed with a proportion of space devoted to each room.
4. Her salary is a small proportion of the company's total income.
5. The proportion of the vote received by each candidate was determined.