In obsolete|lang=en terms the difference between bulk and commodity
is that
bulk is (obsolete) the body while
commodity is (obsolete) self-interest; personal convenience or advantage.
As nouns the difference between bulk and commodity
is that
bulk is size, mass or volume while
commodity is (obsolete) convenience; usefulness, suitability.
As an adjective bulk
is being large in size, mass or volume (of goods, etc).
As a verb bulk
is to appear or seem to be, as to bulk or extent.