Based on what the root word phon means, the word phonometry means "The measurement of sound"
Explanation:
Phon is a Greek root word that means "sound" it can be used as a prefix and as a suffix as well, in this case, we have it as a prefix followed by metry which comes from meter that is related to the measurement of anything, then both together give us the definition that Phonometry is the measurement of sound with a phonometer.
The audience applaud because even when we cut the sentence this part by itself makes sense and just a tip, independent clauses are usually towards the end of a sentence