Army unit (5)
'army unit' is the definition.
(division is a kind of army unit)
This is all the clue.
(Other definitions for division that I've seen before include "part of force" , "Group of football teams" , "mathematical operation" , "Section of organisation" , "Major unit of an organisation or maths function" .)
'army unit' is the definition.
(regiment is a kind of army unit)
This is the entire clue.
(Other definitions for regiment that I've seen before include "Force under colonel" , "Organise; army unit" , "Section of an army" , "Military group" , "Army grouping" .)
'army unit' is the definition.
(corps is a kind of army unit)
This is all the clue.
(Other definitions for corps that I've seen before include "Large body of troops" , "Military body" , "Branch of an army" , "ballet group" , "army band" .)