The term 'OAK FEATURE' can be broken down into two crossword solutions: TRUNK (5 letters) and ACORN (5 letters). The TRUNK of an oak tree is its main stem, which is typically thick and strong. Acorns are the fruit of the oak tree, which are small, hard, and contain a single seed. Oak trees are a type of deciduous tree that are native to many parts of the world, and they are known for their longevity and strength.