fiction
there is NO antonym for envelopes due to the fact that it is a noun.
fact
synonym: truth, actuality antonym: fabrication, lie
FACT or TRUTH
synonym: Fact Antonym: Lie
An antonym or opposite word for myth would be fact. You could also say nonfiction or reality.
Fact. Real life. Non-fiction.
I don't know...there isn't one...and this is a true fact.
truth, reality, certainty, verity
No, Up does not mean down. In fact, "down" is the antonym of "up"!
Possible antonyms are:certainty,fact, reality,realization,substance,verity
Some words don't have antonyms (most, in fact). "Kennel" is one such.