Il‐lu″sion (?), n. [F. illusion, L. illusio, fr. illudere, illusum, to illude. See Illude.] 1. An unreal image presented to the bodily or mental vision; a deceptive appearance; a false show; mockery; hallucination.
To cheat the eye with blear illusions. Milton.
2. Hence: Anything agreeably fascinating and charming; enchantment; witchery; glamour.
Ye soft illusions, dear deceits, arise! Pope.
3. (Physiol.) A sensation originated by some external object, but so modified as in any way to lead to an erroneous perception; as when the rolling of a wagon is mistaken for thunder.
☞ Some modern writers distinguish between an illusion and hallucination, regarding the former as originating with some external object, and the latter as having no objective occasion whatever.
4. A plain, delicate lace, usually of silk, used for veils, scarfs, dresses, etc.
Syn. — Delusion; mockery; deception; chimera; fallacy. See Delusion. Illusion, Delusion. Illusion refers particularly to errors of the sense; delusion to false hopes or deceptions of the mind. An optical deception is an illusion; a false opinion is a delusion. E. Edwards.