Eve of historic event in 1916, for which date's varying with year
I believe the answer is:
easter day
'eve of historic event in 1916 for which date's varying with year' is the definition.
The answer and definition can be both related to time as well as being singular nouns.
Maybe there's a link between them I don't understand?
'eve of historic event in 1916 for which date's' is the wordplay.
I cannot quite see how this works, but
'date' could be 'day' (I have seen 'Particular date' mean 'day' so perhaps 'date' could also mean 'day') and 'day' is found in the answer.
The remaining letters 'easter' is a valid word which might be clued in a way I don't understand.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for easter day that I've seen before include "Egg-giving time" , "eggs on this occasion" , "Time of Christian festival" , "part of holiday?" , "When Christians celebrate the Resurrection" .)