My hubby had a question that I couldn't answer at all so I figured I'd come to the experts.

Was there ever a cocious root to the word precocious. I mean, if precocious is developementally avanced compared to children of the same age, was there a word cocious that meant a child was developping at exactly at the same level as others his age?

Precocious comes from Latin praecox 'premature, ripe before its time, precocious'.The root after the prae- prefix is is the same one that gives us cook.