Phan"tasm (?), n. [L. phantasma. See Phantom, and cf. Fantasm.] [Spelt also fantasm.]
An image formed by the mind, and supposed to be real or material; a shadowy or airy appearance; sometimes, an optical illusion; a phantom; a dream.
They be but phantasms or apparitions.
Sir W. Raleigh.
A mental image or representation of a real object; a fancy; a notion.
Figures or little features, of which the description had produced in you no phantasm or expectation.
© Webster 1913.