1. (in zoology) A form of reproduction in animals in which the developing embryo obtains its nourishment directly from the mother via a placenta or by other means. Viviparity occurs in some insects and other arthropods, in certain fishes, amphibians, and reptiles, and in the majority of mammals. Compare oviparity; ovoviviparity.

2. (in botany)

1. a. A form of asexual reproduction in certain plants, such as the onion, in which the flower develops into a budlike structure that forms a new plant when detached from the parent.

2. b. The development of young plants on the inflorescence of the parent plant, as seen in certain grasses and the spider plant.