Extant means "still existing". It is the opposite of extinct, and can be applied to species and other biological taxa, and also (outside the field of biology and paleontology), cultures and works of culture (e.g. plays, poems) that are currently still in existence.
In biology, the expression is commonly used to refer to or distinguish between living and fossil species. For example, there are approximately 600 extant and 7500 extinct species of cephalopods. (Barnes, 1987).
MAK061016 - adapted from Wikipedia