Two pentatonic scales common to jazz are the major pentatonic scale and the minor pentatonic scale.
The major pentatonic scale begins with a major scale and omits the fourth and the seventh scale degrees: a C major scale is {C, D, E, F, G, A, B}, so a C major pentatonic scale would be {C, D, E, G, A}.
The minor pentatonic scale could more accurately be called a mode, as it comprises the same notes as the major pentatonic scale, but begins on the sixth scale degree of the corresponding major scale. Continuing the example above, A is the sixth scale degree of C major, so the A minor pentatonic scale would be {A, C, D, E, G}.
The nomenclature, "minor pentatonic scale," is confusing, since this scale is actually constructed from a major scale; the term minor is employed in the sense of relative minor.
The minor pentatonic scale with a flattened fifth is sometimes called the blues scale.