Dominant seventh sharp ninth chord
In music, the dominant 7♯9 chord ("dominant seven sharp nine" or "dominant seven sharp ninth") is a chord built by combining a dominant seventh, which includes a major third above the root, with an augmented second, which is the same pitch as the minor third degree above the root, albeit given a different note name. For example, a G dominant dominant 7♯9 chord (G7♯9) consists of the notes G–B–D–F–A♯.
Source: Wikipedia — Dominant seventh sharp ninth chord (CC BY-SA 4.0)