What is the 'Icehouse' effect?

I understand the greenhouse effect but I've been reading up on some scientific journals for my exams and I can't get the concept of Icehouse effect. Some papers are telling me that an Icehouse effect is when there is overall global entrapment in ice. Then how con one be formed when a super continent is present? Seeing as the super continent produces its own 'greenhouse' effect heating the planet? Can anyone help me on this?