Eon (3)
'eon' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for era that I've seen before include "Major division of geological time" , "day" , "US equality law" , "Important historical period" , "Significant time" .)
'eon' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for age that I've seen before include "Period piece" , "Very long time" , "How long something has existed" , "Period of history" , "16/18 [INDUSTRIAL REVOLUTION]" .)