An atmosphere is a surrounding environment or influence. If you and your coworkers talk behind each other's backs, you will create a nasty atmosphere at work.
Atmosphere was invented by seventeenth century Scientists from Greek words for vapor, atmos, and sphere sphaira. The earth's atmosphere is the air and gas surrounding our planet. Atmosphere also describes the feeling of a place. A coffee shop might have a cool, artsy atmosphere. Some plants grow best in a damp atmosphere. Police presence creates a paranoid atmosphere among protesters. In physics, atmosphere is a unit of pressure equal to the air pressure at sea level.