A manuscript written on old sets of questions (5)
I believe the answer is:
exams
'sets of questions' is the definition.
The definition and answer can be both related to communication as well as being plural nouns.
Maybe there's an association between them I don't understand?
'a manuscript written on old' is the wordplay.
'manuscript' becomes 'ms' (abbreviation for manuscript).
'written on' says to put letters next to each other.
'old' becomes 'ex' (prefix meaning former or onetime).
'a'+'ms'='ams'
'ams' after 'ex' is 'EXAMS'.
Can you help me to learn more?
(Other definitions for exams that I've seen before include "summer term commitment?" , "finals?" , "Student assessments" , "GCSE, A-level, etc" , "Important tests" .)