The word fertile means "able to reproduce," but like so many words, that's just the beginning. The fact that she gave birth to eight kids was proof that she was fertile: that she did so in the fertile hills of the wine country helped explain why.
The distance between fertile's literal meaning (able to make babies) and its figurative ones (productive, fruitful, full of potential) is small. A child's imagination is a fertile place; an idea can grow there very easily. Rabbits are famously fertile creatures; they can spawn several generations in a matter of months! Germany's depressed economy after the First World War was fertile ground for the Nazis' toxic brand of self-determination.
