genus of long-necked, long-tailed Jurassic dinosaurs, 1884, coined in Modern Latin in 1878 by U.S. paleontologist Othniel Charles Marsh (1831-1899) from Greek
diploos
"double" (see
diplo-
) +
dokos
"a bearing-beam," connected to
dekomai
"to take, accept, receive," as an agent-noun, so, properly, "which takes on (the load or covering)," from suffixed form of PIE root
*dek-
"to take, accept." The dinosaur was so called for the peculiar structure of the tail bones.