Arrival of notice archdeacon originally typed (6)
I believe the answer is:
advent
'arrival of' is the definition.
(I've seen this before)
'notice archdeacon originally typed' is the wordplay.
'notice' becomes 'ad'.
'archdeacon' becomes 'ven'.
'originally' suggests taking the first letters.
The first letter of 'typed' is 't'.
'ad'+'ven'+'t'='ADVENT'
(Other definitions for advent that I've seen before include "Church season" , "approach" , "Pre-Christmas season for Christians" , "Time approaching Christmas" , "sort of calendar" .)