With the given clues, unscramble the letters to make a meaningful word.
BDECILE – Unit of loudness of sound.

Hint: We need to understand the given clue in order to unscramble the given letters to get the required word. It is given that the letters constitute a word which is the unit of the loudness of the sound. We can check the units of loudness for this.

Complete answer: We know that the loudness of the sound is a characteristic of the sound wave produced. It is the physical quantity which is directly proportional to the amplitude of the oscillation of the particles in the medium in which the sound travels. The higher the amplitude, the sound will be louder to the listener.
Since, loudness is the quantity which we can sense with our ears, we need to quantise the physical quantity in some comparable way. Here loudness, therefore, has a unit which is used to measure it on a standard scale.
The Bel (B) or the decibel (dB) is used as a standard for comparing the loudness of the sounds. It is measured as the logarithmic value of the power of the sound or the intensity of the sound produced. The decibel is one-tenth of a bell. We use these quantities to compare the loudness between two different sounds.
In our case, the scrambled letters are – BDECILE. We can rewrite these letters in the correct order to get the word DECIBEL, which is a unit of loudness.
So, the word DECIBEL is the required solution.

Note:
The decibel system is defined such that the nil or zero decibel is the least loudness of sound that is sensible to a human ear. Any loudness below this sound is highly feeble and insensitive to us. The maximum loudness is 130dB above which our ears might get hurt.