Rellie is residing for a month after Seder (5)
I believe the answer is:
nisan
'seder' is the definition.
Both the answer and definition are singular nouns.
Maybe they are linked in a way I don't understand?
'rellie is residing for a month' is the wordplay.
I cannot really see how this works, but
'is' is within the answer.
'a' could be 'an' and 'an' is found in the answer.
A single letter 'n' remains which might be clued in a way I don't understand.
This explanation may well be incorrect...
'after' acts as a link.
Can you help me to learn more?
(Other definitions for nisan that I've seen before include "month in Israel" , "when Passover begins" .)