(US LAW) nonprofit corporation;
legal status permitted to certain types of organizations under Treasury Regulations section 501(c)(3) that exempts it from taxation.
The 501(c)(3) is quite easy to organize, especially if one wants to funnel
money from donors to some form of activism. It was first
made available in 1934 but has become extremely common since 1986 because successive rulings greatly loosened restrictions on electioneering for 501(c)(3) entities.
Often 501(c)(3) entities engaged in
politics are affiliated with an almost-identical 501(c)(4) entity, which has EVEN WEAKER limitations on electioneering.