shēn​tǐ​zhì​liàng​zhǐ​shù

body mass index

  1. body
    the physical body of a person or animal
  2. mass
    a physical measure of an object's inertia and gravitational attraction, usually measured in kilograms
  3. index
    A number used in statistics to show how much a value (such as prices or productivity) has changed compared to a base period.