The most common and most likely answer to this crossword clue is the 4 letter word DUET
I've seen this crossword clue in The Daily Telegraph
D
U
E
T
More clues leading to the result DUET
- Proper time to perform together
- Performance expected on time
- Deserts partner in the middle — of this?
- Proper time for a little music
- Proper time for performance by two
- Enough time for song
- Expected tenor to give performance
- Couple about to give birth left at last
- Performers to be paid on time?
- Owed tenor for music
Buddy explains!

The straight part
We know that "a piece for two" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case a piece for two = duet.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does DUET mean?
DUET noun- A musical composition in two parts, each performed by a single voice (singer, instrument or univoce ensemble).
- A song composed for and/or performed by a duo.
- A pair or couple, especially one that is harmonious or elegant.
- To perform a duet.
- (of pairs of animals) To communicate (warnings, mating calls, etc.) through song.
- To perform (sing, play, etc.) as a duet.
- (of two people) To say at the same time, to chorus.