1. Relating to not being contemporary or existing at different times: There have been allochronic populations of species living, growing, or reproducing during different seasons of a year.
2. Pertaining to different segments of geologic time: Susie wanted to know what plants occurred in the allochronic periods of the Earth's history.

A form of organic evolution starting from a life-giving reproduction that happens due to a change in time of breeding which lessens or stops gene flow between two groups of a species: Allochronic speciation is the process of developing different biological groups as a result of members of the population that have different breeding seasons or patterns, or differing in the use of time during the day or night, rather than through geographic separation.