The augmented seventh chord, often denoted as "aug7" or "+7", is a distinct and colorful chord quality which commands attention through its rich and dissonant sound. It is constructed by taking a dominant seventh chord and raising the fifth by one half step, resulting in the formula: root, major third, augmented fifth, and minor seventh. This chord is particularly useful in creating tension that demands resolution, making it popular in genres such as jazz and blues. Often used in transitional passages, it serves as a pivotal point in modulations and can add unexpected flavor to chord progressions.