The most common and most likely answer to this crossword clue is the 6 plus 6 letter word CARBON DATING
I've seen this crossword clue in Independent
C
A
R
B
O
N
D
A
T
I
N
G
More clues leading to the result CARBON DATING
- Determining age of a metal key found by 007 beside vehicle
- Band in go-cart rubbished ageing process
- Chemical analysis of cat DNA. Boring? Exciting!
- Disclosure of age making bubbly nurses down
- Carrying around a snack, can say how old it is
- & 28a. Stick with aspirin tablets, primarily being concerned about aging process
- Ageing band got in scuffles on coach
Buddy explains!
The straight part
We know that "Ageing" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case ageing = carbon dating.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 CARBON DATING mean?
CARBON DATING verb- To gauge the age of (an organic material) by comparing the ratio of carbon isotopes.