Era (3)
'era' is the definition.
(both can mean a long period of time)
This is all the clue.
(Other definitions for age that I've seen before include "Get old" , "Mature, grow in years" , "Long period" , "Historic period" , "Era; grow old" .)
'era' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for eon that I've seen before include "Huge time period" , "Long period of time" , "Age, epoch" , "thousand million years" , "An immense time" .)
'era' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for time that I've seen before include "Age" , ""The enemy"" , "> moment" , "It's done in prison" , "it may be Central European" .)
'era' is the definition.
(synonyms)
This is all the clue.
(Other definitions for epoch that I've seen before include "Aeon" , "A great age from which dates are reckoned" , "Period, era" , "Age, time span" , "A particular period of history" .)