|Also called: abiogenesis a theory, widely held in the 19th century and earlier but now discredited, stating that living organisms could arise directly and rapidly from nonliving material|
|an arrangement of five objects, as trees, in a square or rectangle, one at each corner and one in the middle.|
|a screen or mat covered with a dark material for shielding a camera lens from excess light or glare.|
The supposed development of living organisms from nonliving matter, as maggots from rotting meat. The theory of spontaneous generation for larger organisms was easily shown to be false, but the theory was not fully discredited until the mid-19th century with the demonstration of the existence and reproduction of microorganisms, most notably by Louis Pasteur. Also called abiogenesis.