The "harvest moon" and "hunter's moon" are traditional terms for the full moons occurring during late summer and in the autumn, in the northern hemisphere usually in August, September and October respectively.
The "harvest moon" is the full moon closest to the autumnal equinox (22 or 23 September), and the "hunter's moon" is the one following it.
The names are recorded from the early 18th century. OED for "harvest moon" cites a 1706 reference, and for "hunter's moon" a 1710 edition of The British Apollo, where the term is attributed to "the country people".
The names became traditional in American folklore, where they are now often popularly attributed to the Native Americans.
The orange/yellow colour of the harvest moon is due to its closeness to the horizon, rather than being unique to harvest moons.
Reference: Wikipedia