Dosage (noun)

1. The amount of a medicine, drug, or vitamin that is taken at one time.
2. The amount of a substance or agent added to or used in something else, such as a chemical reaction or medical treatment.

Origin:

Early 19th century, from french, from dos 'dose'.

Examples:

1. The doctor prescribed a specific dosage of medicine to be taken three times a day.
2. The dosage of insulin was carefully regulated to prevent hypoglycemia.
3. The chemist carefully measured the dosage of each chemical to ensure the reaction proceeded as expected.
4. The label on the medication bottle indicated the recommended dosage.
5. The nutritionist recommended a daily dosage of vitamin C to support a healthy immune system.