In obsolete terms the difference between about and fact
is that
about is preparing; planning while
fact is feat.
In archaic terms the difference between about and fact
is that
about is in circuit; circularly; by a circuitous way; around the outside; in circumference while
fact is action; the realm of action.
As a preposition about
is in a circle around; all round; on every side of; on the outside of.
As an adverb about
is not distant; approximate.
As an adjective about
is moving around; astir.
As a noun fact is
action; the realm of action.
As an interjection fact is
used before making a statement to introduce it as a trustworthy one.
As an initialism FACT is
federation Against Copyright Theft.