a reference work (often in several volumes) containing articles on various topics (often arranged in alphabetical order) dealing with the entire range of human knowledge or with some particular specialty
a dive in which the diver throws the feet forward to complete a full backward somersault and enters the water feet first and facing away from the diving board
a person who gains (gains an advantage or gains profits); "she was clearly the gainer in that exchange"
a rocket-propelled guided missile that can escape the earth's atmosphere; makes observations of the solar system that cannot be made by terrestrial observation