Environmentally friendly (also eco-friendly, nature friendly, and green) are terms that refer to objects that people buy (called "goods"), services, laws, and rules that either do not harm the environment or do very little harm to it. To make people who buy the goods or services know that they are environmentally friendly, environmentally friendly goods and services often are marked with "eco-labels". But because there is no single type of eco-label, the International Organization for Standardization thinks that these labels do not mean much because they could mean different things.