No, 14 to 16 are not "children". they are underage, that is not the same thing.
If you look it up in the dictionary. the traditional definition for a child is someone between the ages of infancy and puberty (which is 12 year old).
There is an alternative more recent definition of "someone under the age of majority". this definition is stupid and few people use it.
Also age of majority varies by country between the ages of 15 and 21.
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and can vary even further by religion. example in judaism the age of majority is 13
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Age of majority is extreme arbitrary. And few people would call someone who is 20 years and 11 months old a "child" just because he is under the age of majority in his country.
So... childhood ends at 12. at which point you are an adolescent