What is the measure of body weight relative to height, commonly referred to?

Body mass index (BMI) is the standard measure used to assess body weight in relation to an individual's height. It provides a numerical value that helps categorize individuals into different weight classifications, such as underweight, normal weight, overweight, and obese. The formula for calculating BMI is weight in kilograms divided by height in meters squared (kg/m²). This measure is widely used in health and fitness contexts because it offers a simple, standardized way to evaluate body weight trends within populations and helps identify potential health risks associated with weight categories.

The other choices are not recognized scientific terms for this measure. "Body weight index" and "weight ratio" do not correspond to any established metrics. While "height-to-weight ratio" could imply a relationship between height and weight, it does not accurately reflect the mathematical approach or standardized method that BMI represents. Thus, body mass index is the correct and precise terminology for describing this concept.