The term 'POP IN A BOTTLE' can be summarized by two crossword solutions: COLA (4 letters) and SODA (4 letters). Both terms refer to a type of carbonated beverage that is typically served in a bottle or can. COLA is a type of sweetened, flavored carbonated beverage that is usually made with cola nuts, while SODA is a generic term for any type of carbonated beverage. Both types of beverages are popular around the world and are often served in bottles or cans.