By order, prepare to publish about a hundred (5)
I believe the answer is:
edict
'by order' is the definition.
'edict' can be an answer for 'order' (I've seen this before). I'm unsure of the 'by' bit.
'prepare to publish about a hundred' is the wordplay.
'prepare to publish' becomes 'edit' (I've seen this before).
'about' is an insertion indicator.
'a hundred' becomes 'c' (Roman numeral).
'edit' enclosing 'c' is 'EDICT'.
Can you help me to learn more?
(Other definitions for edict that I've seen before include "Formal order" , "Regulation" , "Proclamation, law" , "Formal announcement" , "Legally-binding order" .)