Ratio (noun)

1. The relative size or amount of one thing to another, especially within a specific set or group.
2. The relationship between two similar or related things, often expressed as a numerical value.

Origin:

Late 16th century: from latin, from ratio 'reason, calculation', from ratus 'calculated'. the original sense was 'reason, principle, or plan for doing something', later 'proportion or relationship between things' (mid 17th century).

Examples:

1. The ratio of men to women in the room was 3 to 2.
2. The company wants to maintain a debt-to-equity ratio of 1 to 2.
3. The doctor recommended a protein-to-carbohydrate ratio of 3 to 5 for a healthy diet.
4. The ratio of wins to losses for the team was 7 to 3.
5. The teacher demonstrated how to find the ratio of the lengths of two similar figures.