The most common and most likely answer to this crossword clue is the 5 plus 4 letter word NERVE CELL
I've seen this crossword clue in Financial Times
N
E
R
V
E
C
E
L
L
More clues leading to the result NERVE CELL
- One conveying an impulse from steel dungeon
- Tiny transmitter in cavity under bottle
- Tiny transmitter in bottle with battery
- Around back of tramcar there’s constant shifting about, little room for conductor
- Clever lens almost transformed neuron
- Face American mobile signal transmitter
- Clever, Len repaired part of a ganglion
Buddy explains!
The straight part
We know that "Tiny transmitter" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case tiny transmitter = nerve cell.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.