Third sector refers to the part of the economy that includes charity and religious work, philanthropy, and volunteerism. 

“第三部门”指的是经济体的慈善机构和事业、宗教工作、志愿服务等领域。

Most people understand the role of governments and corporations in society and know the terms "public sector" and "private sector." However, few people know anything about a third sector of society that is focused on meeting the needs of citizens in communities. 

多数人都理解政府和企业在社会中的角色，也知道“公共部门”和“私人部门”。然而，很少有人知道社会的“第三部门”，第三部门关注于满足社区中公民的需要。