I came across this on this site:
C Ionian is C D E F G A B, whereas C Dorian is C D E♭ F G A B♭
The WWHWWWH is for Ionian.
What is the equivalent for the other modes?
Modes are what we call rotations of the major scale. This means that we can start off with the major-scale interval pattern and just rotate it to begin at different places to create the other modes.
WWHWWWH Ionian (equivalent to the major scale) WHWWWHW Dorian HWWWHWW Phrygian WWWHWWH Lydian WWHWWHW Mixolydian WHWWHWW Aeolian (equivalent to the natural minor scale) HWWHWWW Locrian
Another way to conceptualize this is by starting with the C-major scale. If you begin on C (the first pitch of the major scale), it's C Ionian. If you rotate and begin on D (the second pitch), it's D Dorian. Beginning on the third pitch will be E Phrygian, and so on.
In the above case, some would then call C major the "parent scale" of all modes that use that collection.
Adding to Richards (as ever) superb answer, another way to look at modes with start note (home) of, in this case, C, is to track back.
So - C Ionian is rooted on C.
C Dorian starts on the second major scale note of Bb.
C Phrygian starts on the third maj. scale note of Ab.
C Lydian starts on the fourth maj. scale note of G.
C Mixolydian starts on the fifth maj. scale note of F.
C Aeolian starts on the sixth maj. scale note of Eb.
C Locrian starts on the seventh maj. scale note of Db.
As Richard quoted, the pattern of notes in order will always be from T T S T T T S T T S T T T S etc. T= tone, S= semitone.
And each mode uses the notes from each quoted major scale.
I can't add to the excellent explanations that Richard and Tim have already given here. But anyone interested in modes will almost certainly find Leonard Bernstein's lecture on the subject as interesting as I did (and still do) when it aired on TV 50 years ago:
Bernstein not only gives the explanation that Richard and Tim have provided, but shows a lot of practical examples from all sorts of different music styles.
While rotations of the major scale intellectually explains the structure of modal tone intervals, and are easily "seen" on a keyboard, I have found it more useful in practice to learn modal scales by remembering which notes are flattened or sharpened with respect to the major scale.
For example dorian flattens 3 and 7, so in the key of D, instead of F# and C# we get F and C, making the scale equivalent to the C scale, but starting on D.
From this perspective, we get these scale degrees (based on the major scale):
Ionian 1 2 3 4 5 6 7 1 common (major scale) Dorian 1 2 ♭3 4 5 6 ♭7 1 common Phrygian 1 ♭2 ♭3 4 5 ♭6 ♭7 1 rare except Spanish and moorish Lydian 1 2 3 #4 5 6 7 1 rare except some Eastern and liturgical Mixolydian 1 2 3 4 5 6 ♭7 1 common Aeolian 1 2 ♭3 4 5 ♭6 ♭7 1 common (relative minor) Locrian 1 ♭2 ♭3 4 ♭5 ♭6 ♭7 1 very rare
Some modes, especially Dorian and Mixolydian, are common in Celtic music. As an aside, dorian is often confused with aeolian (relative minor of the key), but the raised 6th scale degree gives dorian away.