Origin: Latin suffix -tion
Hallucination has 4 different meanings across 1 category:
illusory perception; a common symptom of severe mental disorder
a mistaken or unfounded opinion or idea
"he has delusions of competence"
"his dreams of vast wealth are a hallucination"
an object perceived during a hallucinatory episode
"he refused to believe that the angel was a hallucination"
A sensory perception of something that does not exist, often arising from disorder of the nervous system, as in delirium tremens; a delusion.
The word comes from the Latin hallucinatus, meaning to wander or be deluded. It entered English via the verb hallucinate, with the earliest recorded use appearing in the works of Sir Thomas Browne.