The most common and most likely answer to this crossword clue is the 9 letter word DECIMETRE
I've seen this crossword clue in The Times
D
E
C
I
M
E
T
R
E
More clues leading to the result DECIMETRE
Buddy explains!

The straight part
We know that "Distance" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case distance = decimetre.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 DECIMETRE mean?
DECIMETRE noun- An SI unit of length equal to 10-1 metres. Symbol: dm