Phan"tasm (?), n. [L. phantasma. See Phantom, and cf. Fantasm.] [Spelt also fantasm.] 1. 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.

2. A mental image or representation of a real object; a fancy; a notion. Cudworth.

Figures or little features, of which the description had produced in you no phantasm or expectation.
Jer. Taylor.