In the medical term, mononucleosis, this means there is one nucleus present in the leukocytes (white blood corpuscles) in the blood.

In the medical term, monopodia, this means a conditon of having only one foot where usually both feet are fused together to make one foot.

In the chemical structure, monosodium glutamate, this means there is one sodium present in the chemical structure. It is sodium salt of glutamic acid, which has a meatlike taste used to flavor foods, especially in the Orient. When it is ingested in large amounts, it typically causes chest pain, a sensation of facial pressure, headaches, burning sensation and excessive sweating. These symptoms collectively actually have a name called, "Chinese Restaurant Syndrome." It is manufactured and sold under various names such as; Ajinomoto, Accent and Vetsin.