The most common and most likely answer to this crossword clue is the 5 letter word LITRE
I've seen this crossword clue in The Guardian
L
I
T
R
E
More clues leading to the result LITRE
- Volume was illuminating, with accompanying note
- Over a pint needed to get engineer tiddly
- Settled on measure of capacity
- In Paris, bed group of soldiers in unit
- Illuminated note in volume
- Tiler misread measure
- Left Italian red, not finishing contents of carafe?
- Partly full, it retains a quantity of liquid
- Amount of liquid in pail I trebled
- Extreme pieces of literature put together in volume
Buddy explains!

The straight part
We know that "quantity of liquid" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case quantity of liquid = litre.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 LITRE mean?
LITRE noun- The metric unit of fluid measure, equal to one cubic decimetre. Symbols: l, L, ℓ
- A measure of volume equivalent to a litre.