Vortaro de Esperanto
The Vortaro de Esperanto (English: Dictionary/Lexicon of Esperanto), published by Kazimierz Bein in 1911, was the first monolingual dictionary ever published in Esperanto. It is considered the predecessor of the Plena Vortaro de Esperanto, published in 1930, and of the current Plena Ilustrita Vortaro, whose last edition came out in 2020.