An eclipse is an astronomical event that occurs when one celestial object moves into the shaow of another. The term is derived from the ancient Greek noun έκλειψις (ékleipsis), from verb εκλείπω (ekleípō), "I cease to exist," a combination of prefix εκ- (ek-), from preposition εκ, εξ (ek, ex), "out," and of verb λείπω (leípō), "I am absent". When an eclipse occurs within a stellar system, such as the Solar System, it forms a type of syzygy—the alignment of three or more celestial bodies in the same gravitational system along a straight line.