What is Green? Reconsidering the Definition of Green/Eco

Abstract
Green means a kind of consideration by which society tries to maintain a positive environmental situation. It can be said that it is also motivation by which society aims at sustainability with the earth ecosystem. It is a key point for how to discard entropy. The sustainability for human beings can be attained to extend the current status in near future.
The life cycle assessment is a powerful technique to judge whether a product is green, and it is necessary to develop a new technique to integrate the concept of risk assessment, which normally evaluates the influence on human health. A trial version of a green index to evaluate green-chemistry is also described.

Key words: green, the earthecosystem, sustainability, the life cycle assessment, green index