The most common and most likely answer to this crossword clue is the 9 letter word ELECTRODE
I've seen this crossword clue in Independent
E
L
E
C
T
R
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D
E
More clues leading to the result ELECTRODE
- Choose Wagner’s last lyrical work for conductor
- Conductor travelled with those chosen
- Choose baton with European conductor
- Conductor’s chosen way to be announced
- Choose staff needed on European terminal
- Return baton given to English conductor
- Conductor’s poem on demented Lecter
- Conductor travelled to support those chosen
- Conductor designate went by train
- A shocking thing: having an even keel, rescuer stepped in
Buddy explains!

The straight part
We know that "Conductor" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case conductor = electrode.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 ELECTRODE mean?
ELECTRODE noun- The terminal through which electric current passes between metallic and nonmetallic parts of an electric circuit
- A collector or emitter of electric charge in a semiconducting device