Two-person group (3)
I believe the answer is:
duo
I believe this is a double definition.
'two' is the first definition.
(duo is a kind of two)
'person group' is the second definition.
(I know that duo is a type of musical group)
(Other definitions for duo that I've seen before include "Item" , "Musical pair" , "rejected Arab's lute" , "A team of two" , "Music for two" .)