Family enthralled by magic lantern (4)
I believe the answer is:
clan
'family' is the definition.
(I've seen this before)
'enthralled by magic lantern' is the wordplay.
'enthralled by' says the answer is hidden in the clue.
'CLAN' is hidden in the letters of 'magic lantern'.
(Other definitions for clan that I've seen before include "Group with common ancestor, like the Campbells" , "Tribe or collection of families under a cheiftain" , "Kin group" , "Tribal group with common ancestor" , "Kinship group" .)