Pavilions are a form of tent used in the SCA. They sometimes have at least one open side which is used as a verandah during the day, and closed up during the night (or when it rains). Some people put a lot of effort into their pavilions. There are larger pavilions which are owned by baronies and so forth (as well as by people who think that bigger is better).
Pavilion is also commonly used in the SCA as a term to distinguish a period style tent from a mundane tent, such as the ubiquitous dome tent or nylon A frame. Re-enactors use the term period tent or a term used to define the tent style geteld, Viking, etc.
At re-enactment events those with tents not appropriate for the time frame for the event are required to set them up out of sight from the event. It is unheard of for a re-enactment group of any standing, to not possess enough period tents to house a signicant proportion of their membership.
Making a Tent
Interestingly, making a period style tent is about as expensive as buying a decent modern tent that is much smaller, and oft-times less practical. Gwynfor Lwyd's 5.5m x 3m Saxon geteld (designed and constructed by House Woodrose) is about $500 of materials and took 28 hours from go to woah, so the only additional cost is time (and how you cost your time is your business!).