What is the definition of the word "child".

[jp11]

6. You got it,

when you want to entice an emotional response you'll use the more 'weak' sounding term, child, teen, kid, etc. I've heard people call 19 year old people kids, "oh their just kids" to elicit empathy as if they were somehow more innocent because you called them a 'kid'.

The whole point is how the person or people using the term feel about the person in the situation which is why they choose the term they do to describe them.