'Chamaemelum' is a genus name in botany, which includes a few species of herbs in the family Asteraceae. The most common and well-known species is Chamaemelum nobile, also known as Roman chamomile or English chamomile. This plant is native to western Europe and North Africa and has been used traditionally for medicinal purposes, particularly for its calming and anti-inflammatory effects.

The medical definition of 'Chamaemelum' would refer to the therapeutic properties and uses of this plant or its extracts in medicine. Chamaemelum extracts, especially those derived from the flowers, have been used in various forms of traditional medicine to treat a variety of conditions, including anxiety, insomnia, digestive disorders, skin irritations, and inflammation.

The active compounds in Chamaemelum include volatile oils (such as bisabolol and chamazulene), flavonoids, and coumarins, which have been shown to possess anti-inflammatory, antispasmodic, and sedative properties. However, it is important to note that the scientific evidence supporting the medicinal use of Chamaemelum is still limited, and more research is needed to establish its safety and efficacy in clinical settings.

Therefore, when using 'Chamaemelum' in a medical context, it is essential to specify the particular species and plant part being referred to, as well as the intended medicinal use and any relevant scientific evidence or safety considerations.