Here's how we can figure it out:
* Clue 1: The sentence mentions a "horn". This suggests that the root word might be related to horns.
* Clue 2: The sentence describes a "horn overflowing with fruits and vegetables". This suggests that the root word might be related to abundance or plenty.
"Cornu" is a Latin word that means "horn".
Therefore, the root word "cornu" in "cornucopia" gives us the meaning of a horn, which is then connected to the concept of abundance, resulting in a "horn of plenty".