Figment, n.
Etymology: [L. figmentum, fr. fingere to form, shape, invent, feign. See Feign.]
An invention; a fiction; something feigned or imagined. Social figments, feints, and formalism. Mrs. Browning. It carried rather an appearance of figment and invention . . . than of truth and reality. Woodward.
Shades of meaning
Fernald has no entry of its own for figment; he lists it under fiction.
Where he writes about it:
A figment is something imaginary which the one who utters it may or may not believe to be true; we say, "That statement is a figment of his imagination." The story may be either true or false, and covers the various senses of all the words in the group. — from fiction