bone age

https://doi.org/10.1351/goldbook.10467

Average age at which children reach a given stage of bone maturation, denoting the stage of skeletal development of an individual fetus or child.

Note: A child’s current height and bone age can be used to predict adult height.
Source:
PAC, 2016, 88, 713. 'Glossary of terms used in developmental and reproductive toxicology (IUPAC Recommendations 2016)' on page 731 (https://doi.org/10.1515/pac-2015-1202)