cell cycle phase GO:0022403 One of the distinct periods or stages into which the cell cycle is divided. Each phase is characterized by the occurrence of specific biochemical and morphological events. Note that this term should not be used for direct annotation. If you are trying to make an annotation to x phase, it is likely that the correct annotation is 'regulation of x/y phase transition' or to a process which occurs during the reported phase (i.e mitotic DNA replication for mitotic S-phase). To capture the phase when a specific location or process is observed, the phase term can be used in an annotation extension (PMID:24885854) applied to a cellular component term (with the relation exists_during) or a biological process term (with the relation happens_during). biological_process biological phase