September is Etymology Month (29)

КОСМОНАВТ [kosmonávt] 'spaceman'. based on Gk. kósmos 'space', naútes 'sailor', widely known after the first manned space flight by Jurij Gagarin on 12 April 1961 (космонавтика 'outer space exploration' is recorded in dictionaries from 1958). Cf. астронавт 'astronaut', used mainly of US spacemen, and occasionally астрокосмонавты, used in 1975 during the joint Apollo Sojuz flight (ЭПАС - Экспериментальный полёт Аполлон-Союз 'Apollo-Sojuz Experimental Flight).