Wiktionary
n. (context politics English) A socialist ideology, originating in Trotskyism, which aims to support the organised working class, as opposed to capitalism, or another prominent force, originally Stalinism and in the 1990s and 2000s often Islamism.
Wikipedia
The third camp, also known as third camp socialism or third camp Trotskyism, is a branch of socialism which aims to oppose both capitalism and Stalinism, by supporting the organised working class as a "third camp".
The term arose early during the Second World War, and refers to the idea of two "imperialist camps" competing to dominate the world: one led by the United Kingdom and France and supported by the United States, and the other led by Nazi Germany and supported by Fascist Italy.
Usage examples of "third camp".
By the third camp out of the city, Perrin half-expected to see Sulin and Nandera's fight repeated between Wise Ones.
Two secondary camps were cited and occupied but it was obvious that a third camp to the far east would have to be established to continue exploration of the easterly land mass.
There they made their third camp, hauling up what they needed from below with their ropes.