The term 'champagne feature' is a reference to the bubbles that are present in champagne. The crossword solution for this term is 'BUBBLE, ' which is a 6-letter word. Champagne is a sparkling wine that is produced in the Champagne region of France. It is made from a blend of grapes and is known for its effervescence, or bubbles, which are created by carbon dioxide gas. The bubbles are an important part of the flavor and texture of champagne and are a defining feature of the beverage.