Wiktionary
n. (context music English) a minor key with the notes D♯, E♯, F♯, G♯, A♯, B, C♯
Wikipedia
D-sharp minor or D minor is a minor scale based on D-sharp, consisting of the pitches D, E, F, G, A, B, and C. For the harmonic minor, C is used instead of C. Its key signature has six sharps.
E minor is its enharmonic equivalent. Its relative major is F major (or enharmonically G major), and its parallel major is D major, usually replaced by E major, since D major's two double-sharps make it impractical to use.
Changes needed for the melodic and harmonic versions of the scale are written in with accidentals as necessary.
D minor is infrequently used as the principal key center of pieces in the Classical era. More common is notation in E minor, which is a relatively manageable key for many brass instruments and woodwinds.