A specialized resting state that cells enter in response to cues from the cell's environment. Quiescence is characterized by the absence of cell growth and division, by a reprogramming of global gene expression, and by changes characteristic of the organism and specific cell type. Depending on external conditions, quiescence may persist until cell death or cells may resume cell growth and division. In some cell types or under certain conditions, cellular metabolism may proceed.
Note that terminally differentiated cells in higher eukaryotes are typically quiescent but metabolically active. 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).