A stiffener or two (5)
I believe the answer is:
brace
I believe this is a double definition.
'a stiffener' is the first definition.
(thesaurus)
'two' is the second definition.
(brace can mean two of something)
'or' acts as a link.
(Other definitions for brace that I've seen before include "Secure" , "Stanchion" , "Support - couple" , "Pair; hand drill" , "Two - supporter" .)