Four Pillars

The Four Pillars of the Greens originally established in Europe in the 80s are:

ecological wisdom: "Our environment nurtures humanity, and thus, humans for the sake of survival, are wise to consider our environment in thought, word and action." - Dana L. Miller

nonviolence - in the Gandhian civil disobedience sense not the quietism sense, sometimes alternate peace and nonviolence or de-escalation

social justice - which should not be confused with being a Social Democrat

participatory democracy - sometimes generalized to grassroots democracy as there is now a vocabulary of many related terms of which "participatory" is only one

For more depth see en: Wikipedia: Four Pillars.

The Four were later, in the Global Greens Charter, extended to Six Principles in part due to influence of the Ten Key Values of US and Canadian Greens, in which there was special status given to specific Sustainability and Diversity concerns that seemed to be, to the original European drafters of the Pillars, implied as consequences of the Four.