A comfort zone is a familiar psychological state where people are at ease and (perceive they are) in control of their environment, experiencing low levels of anxiety and stress.
Judith Bardwick defines the term as "a behavioral state where a person operates in an anxiety-neutral position."[1] Brené Brown describes it as "Where our uncertainty, scarcity and vulnerability are minimized—where we believe we'll have access to enough love, food, talent, time, admiration. Where we feel we have some control."[2]