One half step below the note. In other words; to go from D to C would be a whole step, to go from D to D flat would be a half step.
That would be either called C# or Db.
C-sharp. The leading tone is one half-step below the tonic.
A whole step above C sharp (C#) is D sharp (D#). In music, a whole step consists of two half steps, and moving from C# to D# involves skipping the note D, which is a half step above C#.
In music theory, a major second interval consists of one whole step and one half step. For example, if you start on the note C, moving to D (a whole step) and then to D♯ (a half step) gives you the major second interval from C to D. This interval is fundamental in constructing scales and harmonies in Western music.
Generally, the sharp and flat signs are known as accidentals. They alter the pitch of the note. As an example, D sharp is a half-step higher than D where D flat is a half step lower.
An interval is the distance between two pitches. These intervals are measured in half-steps and whole steps. For example, a half-step is like C to Db. A whole step would be C to D. A major scale is made up of these steps as so: C MAJOR Whole step, Whole step, Half step, Whole step, Whole step, Whole step, Half step. C to D, D to E, E to F, F to G, G to A, A to B, B to C WWHWWWH You may have noticed that from E to F and from B to C it was a half step just as if it were from C to Db. This is because these pitches are simply a half step away from each other.
half a step down, otherwise known as open d# tune all the strings down half a step
F sharp
There are two half-steps in the key of b: D to E flat and A to B flat.
2 sharps is D Major or b minor. The two sharps in this key are F# and C#, so you just have to look at the second sharp (C#) and move up a half step for the key (D). To find its minor equivalent, move down three half steps (3 half steps below D is B natural).
If you are asking about the interval it is a minor third (or an augmented second...) In a Chromatic scale starting on C the tones are: C C#(or Db) D D#(orEb) so the whole step (two semitones) would take you from C to D, and then the half step would get you to D#(or Eb... they are enharmonic equivalents, which means that it's the same pitch with two different names)