What is "stelo"

The Stelo ("star"; plural: Steloj) was from 1945 to 1993 a monetary unit of Esperantists, one of whose aims was to achieve a single world currency. Attempts at an earlier currency, the Speso, with derived units like the Spesmilo, were cut short by the First World War. For a time the Universal League (in Esperanto: Universala Ligo), an arm of the Esperanto movement, issued coupons and coins denominated in Steloj, making attempts to link the Stelo to existing currencies on the basis of relative purchasing power in different countries.