The word green has several meanings:

1. A color between blue and yellow. Green is the shade of fresh grass, summer leaves, and limes. It shows up everywhere in nature. Traffic lights use green for “go,” and many maps use green to mark parks or forests. Human eyes are very sensitive to green light.
2. Covered in plants or leafy vegetables. A “green” hill is one that’s grown new grass and leaves, and a “green” salad is full of lettuce and other leafy greens.
3. Connected to protecting the environment. “Green” can mean eco-friendly: green energy (like wind or solar), or green choices (like recycling and reducing waste).
4. Inexperienced. Just like a green banana isn't ready to eat yet, a green dog trainer might not be ready to work with the most challenging dogs yet.
5. The putting area in golf. In golf, the green is the smooth, closely mowed grass around the hole where players putt (even though the entire golf course may look green in color!).