It plays between two and four (4)
I believe the answer is:
trio
'it plays between two and four' is the definition.
The definition suggests a singular noun which matches the answer.
'it plays between' is the wordplay.
'it' becomes ''t' (abbreviation. e.g. in 'tis).
'plays between' becomes 'rio' (I can't justify this - if you can you should believe this answer much more).
't'+'rio'='TRIO'
Can you help me to learn more?
(Other definitions for trio that I've seen before include "wise men?" , "Piece for three players" , "Threesome" , "Bee Gees, Supremes or Andrews Sisters, say" , "Three together" .)