Promise a choice between seven days and one? (4)
I believe the answer is:
word
'promise' is the definition.
(as in 'I give you my word')
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for word that I've seen before include "Promise - unit of language" , "Message" , "See 21" , "See 19" , "Brief statement" .)