phantasm

UK: /ˈfæntæzəm/ US: (fan′taz əm)

WordReference Random House Unabridged Dictionary of American English © 2025

phan•tasm  (fan′taz əm), n. 

1. Mythology an apparition or specter.
2. a creation of the imagination or fancy;
   fantasy.
3. a mental image or representation of a real object.
4. an illusory likeness of something.

Also, fantasm. 

• Latin as above
• Old French
• Greek phántasma image, vision (akin to phantázein to bring before the mind); replacing Middle English fantesme
• Latin phantasma
• 1175–1225

Synonyms

• 1. ghost, vision. See apparition. 
• 4. hallucination, illusion.

Collins Concise English Dictionary © HarperCollins Publishers::

phantasm / ˈfæntæzəm/ noun

1. a phantom
2. an illusory perception of an object, person, etc

Etymology: 13th Century: from Old French fantasme, from Latin phantasma, from Greek; related to Greek phantazein to cause to be seen, from phainein to show

phanˈtasmal, phantasmalian / ˌfæntəzˈmeɪlɪən/, phanˈtasmic, phanˈtasmical adjective