comfort zone

ˈcomfort zone 7 [comfort zone] noun
1. (sometimes disapproving) a place or situation in which you feel safe or comfortable, especially when you choose to stay in this situation instead of trying to work harder or achieve more
• Stepping outside your comfort zone and trying new things can be a great experience.
• We cannot afford to have anyone operating in a comfort zone.

• I'll tell you what drives me crazy— people who have talent but cruise along in the comfort zone.

2. (approving) (especially in sport) a state in which you feel confident and are performing at your best

• I knew if I could find my comfort zone I would be difficult to beat.

Cambridge Advanced Learner's Dictionary

Cambridge Advanced Learner's Dictionary - 4th Edition

comfort zone noun [ C ]

a situation in which you feel comfortable and in which your ability and determination are not being tested:
Rock climbing pushes many people beyond their comfort zones.

Merriam-Webster's Advanced Learner's Dictionary

comfort zone

comfort zone noun, pl ~ zones [count] : a place, situation, or level where someone feels confident and comfortable
• He pushes the players to perform beyond their comfort zone.
• I need to expand my comfort zone and try new things.

comfort zone