The most common and most likely answer to this crossword clue is the 4 plus 5 letter word REED ORGAN
I've seen this crossword clue in Independent
R
E
E
D
O
R
G
A
N
More clues leading to the result REED ORGAN
- Troublesome person with stick always set about music maker
- Roger Dean destroyed harmonium
- Music producer garnered Oscar for new arrangement
- Stops on this red with no gear changes
- Arrangement of 18 24 for keyboard instrument
- Love being transported by gardener playing wind instrument
- Rich girl debuts in Roedean playing keyboard instrument
- Instrument, unusual in one regard
- Music producer to decipher text reported newspaper
- Possibly regal English employed in socialist newspaper
Buddy explains!
The straight part
We know that "harmonium?" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case harmonium? = reed organ.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.