difference b/w tertiary and public sector

The tertiary sector is inside the For-profit or Business sector; it is tertiary behind the primary (raw materials) and secondary (production, encompassing both the manufacturing and service sectors). The tertiary sector is B2B (for example, companies that produce price optimization software to improve productivity and profitability in the retail sector).

The Public sector is government, especially the large regulatory bureaucracies that oversee social justice issues like access, and includes the legislative functions and the courts. Taxation is the funding mechanism for the Public sector, just as sales is the funding mechanism in the For-profit sector.

The Third sector (not to be confused with the tertiary sector) is Nonprofit organizations, funded variously, but in the U.S. and western countries, primarily by charitable donations. In most of the developing world, this sector is referred to as NGOs, Non-Governmental Organizations, since there is usually no tax-free status for these organizations outside the west.