Insulin (noun)

A hormone secreted by the pancreas, which regulates the level of glucose in the blood and is essential for the metabolism of carbohydrates and fats.

Origin:

Late 19th century: from in- "into" + latin insula "island" (because it is produced by the islets of langerhans in the pancreas).

Examples:

1. He needs to take insulin every day.
2. She needs to inject insulin every day.
3. Insulin regulates blood sugar level.
4. Insulin is a hormone that controls blood sugar.
5. Insulin is used to treat diabetes.