1 Actual age from birth regardless of development level. Chronological age is a measure of the time a person has spent out of the womb interacting with the environment. It is inseparably associated with biological growth and experience. Since individual growth rates vary widely, children of the same chronological age show marked differences in strength, motor proficiency, etc.
2 In anthropometry, the difference between the date of observation and the date of birth in years, months, and days.