From the description of boiling here:
Boiling is the rapid vaporization of a liquid, which occurs when a liquid is heated to its boiling point, the temperature at which the vapor pressure of the liquid is equal to the pressure exerted on the liquid by the surrounding environmental pressure.
What I do not understand is the last statement. Does this mean that by definition, boiling cannot occur if we have a homogeneous system (i.e. a closed container of liquid water at equilibrium with its vapor phase) since the definition requires an "atmosphere"? Should we still see the nucleation effect or "bubbles" even in the absence of atmosphere (like in a pressure controlled piston-cylinder assembly)? If so, what is the difference in phase transition between presence of atmosphere or no atmosphere?