A relict is a surviving remnant of a natural phenomenon.

In biogeography, paleontology, and other disciplines concerned with the evolutionary history of plants and animals, a relict population is one found to naturally occur in a restricted area but whose original range was much larger in a previous geologic epoch. To put it another way, a relict (or relic) plant or animal is a taxon that persists as a remnant of what was once a diverse and widespread population. Relictualism occurs when a widespread habitat or range changes and a small area becomes cut off from the whole. A subset of the population is then confined to the available hospitable area, and survives there while the broader population either shrinks or evolves divergently. This phenomenon differs from endemism in that the range of the population was not always restricted to the local region. In other words, the species or group did not necessarily arise in that small area, but rather was stranded, or insularized, by changes over time. The agent of change could be anything from competition from other organisms, continental drift, or climate change such as an ice age.