This is what we found on Wikipedia regarding the Sun Room:

A sunroom, also frequently called a solarium (and sometimes a "Florida room", "garden conservatory", "garden room", "patio room", "sun parlor", "sun porch", "three season room" or "winter garden"), is a room that permits abundant daylight and views of the landscape while sheltering from adverse weather. Sunroom and solarium have the same denotation: solarium is Latin for "place of sun[light]". Solaria of various forms have been erected throughout European history. Currently, the sunroom or solarium is popular in Europe, Canada, the United States, Australia, and New Zealand. Sunrooms may feature passive solar building design to heat and illuminate them.

In Great Britain, which has a long history of formal conservatories, a small conservatory is sometimes denominated a "sunroom". In gardening, a garden room is a secluded and partly enclosed outside space within a garden that creates a room-like effect.