As nouns the difference between eight and octalogy
is that
eight is the digit/figure 8 or
eight can be an island in a river; an ait while
octalogy is (rare) # a set of eight works of art that are connected, and that can be seen either as a single work or as eight individual works they are commonly found in literature, film, or video games.
As a numeral eight
is (cardinal) a numerical value equal to ; the number occurring after seven and before nine.