mother–son
/ˌmʌðəˈsʌn/adjective
1Originally and chiefly Social Sciences. Of, relating to or designating the relationship between a mother and her son.
2 Acupuncture. Designating the law governing the relationships between any two major organs of the body in the five element cycle.
Origin
Early 20th century; earliest use found in Brain: a journal of neurology. From mother + son.