A service club or service organization, in the American sense only, is a voluntary non-profit organization where members meet regularly to perform charitable works either by direct hands-on efforts or by raising money for other organizations. A service club is defined first by its service mission. Secondary membership benefits, such as social occasions, networking, and personal growth opportunities encourage involvement.
A service organization is not necessarily exclusive of ideological motives, although organizations with such defined motives are more likely to identify themselves through their association. Much like the historical religious organizations formed the basis for many of societal institutions, such as hospitals, service organizations perform many essential services for their community and other worthy causes. In the United States, these organizations are commonly tax exempt, 501(c)(3) non-profit organizations.
This sense is not carried in British English. In the UK, Australia, and other Commonwealth countries, a "service club" is likely to be misunderstood as a club for members of "the services", a common expression for the military or uniformed forces.