An octave is the range of 8 notes of a major scale. The first note and last note of a major scale always have the same name. In the C major scale the distance from the first C to the C note above it is one octave (8 notes). The following example is one octave of the C major scale.
Each of the 8 notes in the major scale is given a scale number, or scale degree.
The distance between any two notes is called an interval. In any major scale the interval between the 3rd and 4th notes, and the 7th and 8th notes of the scale is one semitone apart; i.e., they are one fret apart. All other notes are one tone (2 frets) apart.
The following diagram contains all of the notes you have learned so far in the open position. They are all notes of the C major scale, even though the lowest note of the pattern is E and the highest note is G. The key note C is indicated twice. This pattern can be described as the full open position fingering of the C major scale.