A sequence of musical notes in ascending or descending order of pitch.
Most scales are made of seven notes whereby each scale degree is giving a letter name from A to G based on the distance from the root and the previous note. In seven note scales it is typical to describe the pattern in terms of half steps 'H'(one semitone) and whole steps 'W'(two semitones).
For example the scale pattern for a major scale is:
Applying that to a C root of C yields the following:
C D E F G A B C W W H W W W H