Diabolos (toy) evolved from the Chinese yo-yo, which was originally standardized in the 12th century. Chinese yo-yos have a long thin axle, with disc-shaped wheels, while the western diabolo is more cone-shaped. Diabolos are made of different materials and come in different sizes and weights.
The term "diabolo" was not taken from the Italian word for "devil"—"diavolo"—but was coined by French engineer Gustave Phillippart, who developed the modern diabolo in the early twentieth century and derived the name from the Greek dia bolo, roughly meaning 'across throw'.
The Greek word "diabolos" means "the liar" or "the one that commits perjury", from the verb "diaballo", which means "to throw in", "to generate confusion", "to divide", or "to make someone fall". Later the word "diabolos" was used by Christian writers as "the liar that speaks against God". From this meaning come many modern languages' words for "devil" (French: diable, Italian: diavolo, Spanish: diablo, Portuguese: diabo, German: Teufel, Polish: diabeł).
Confusion about the provenance of the name may have arisen from the earlier name "the devil on two sticks", although nowadays this often also refers to another circus-based skill toy, the devil stick. (wiki)