One is arranged in less than a minute (4)
I believe the answer is:
unit
'one' is the definition.
(synonyms)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for unit that I've seen before include "Item combining separate parts" , "Single piece - kitchen cabinet" , "hospital department" , "Detachment of soldiers" , "Self-contained part" .)