"The term “nongovernmental organization” (NGO) is a post-World War II expression which was initially coined by the United Nations (UN). When the UN Charter was adopted in 1945, it was stipulated in Article 71 that NGOs could be accredited to the UN for consulting purposes. Thus, scholars first mainly applied the term NGOs only when referring to those societal actors which are (because of UN criteria) international bodies and engage within the UN context. In recent decades, especially since the 1980s, the term NGO has also become popular for societal actors of all sorts engaged outside the UN framework, internationally and nationally, and has indeed been increasingly adopted more broadly by academics as well as by activists themselves".
Source: Martens, K. 2002. "Mission Impossible? Defining Nongovernmental Organizations". Voluntas: International Journal of Voluntary and Nonprofit Organizations, v. 13, pp. 271–285. <https://link.springer.com/article/10.1023/A:1020341526691>. Accessed 5 May 2020.
"Nongovernmental organization (NGO), voluntary group of individuals or organizations, usually not affiliated with any government, that is formed to provide services or to advocate a public policy. Although some NGOs are for-profit corporations, the vast majority are nonprofit organizations. Some NGOs, particularly those based in authoritarian countries, may be created or controlled by governments. By most definitions, political parties and criminal or violent guerrilla organizations are not considered NGOs. The issues addressed by NGOs run the gamut of human concerns (e.g., human rights, environmental protection, disaster relief, and development assistance), and the scope of their activities may be local, national, or international. Some NGOs fulfill quasi-governmental functions for ethnic groups that lack a state of their own. NGOs may be financed by private donations, international organizations, governments, or a combination of these".
Source: Karns, M. N.d. "Nongovernmental organization". Encyclopedia Britannica. <https://www.britannica.com/topic/nongovernmental-organization>. Accessed 05 May 2020.