Jamboree Shelter is a term used to describe a large TENT that is used for outdoor events such as festivals, concerts, and other gatherings. It is typically made of canvas or other waterproof material and is designed to provide shelter from the elements. The term JAMBOREE Shelter is derived from the word 'JAMBOREE, ' which is an old English term meaning a large gathering of people. The four-letter solution to this crossword puzzle is 'TENT, ' which is an appropriate word to describe this type of shelter.