The most common and most likely answer to this crossword clue is the 9 letter word LOGARITHM
I've seen this crossword clue in The Times
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More clues leading to the result LOGARITHM
- Exponent of record with a beat you can hear
- Part of table no longer needed – in short, it's a piece of wood
- Record a beat on the radio, a powerful number!
- We’re told to record a metre as aid to calculation
- Mathematicians use it to record a recurring pattern, reportedly
- Record a beat sound that’s potentially useful with big numbers
- Listened to record with a beat that comes from power?
- See leaders of Glasgow accepting royal invitation to host marriage function
- It could provide power to record, and harm one tenor by mistake
- They say feller beat system to make product once
Buddy explains!

The straight part
We know that "Part of table no longer needed" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case part of table no longer needed = logarithm.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 LOGARITHM mean?
LOGARITHM noun- For a number x, the power to which a given base number must be raised in order to obtain x. Written \log_b x. For example, \log_{10} 1000 = 3 because 10^3 = 1000 and \log_2 16 = 4 because 2^4 = 16.