The most common and most likely answer to this crossword clue is the 7 letter word GLOTTIS
I've seen this crossword clue in The Guardian
G
L
O
T
T
I
S
Buddy explains!
The straight part
We know that "part of vocal apparatus" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case part of vocal apparatus = glottis.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 GLOTTIS mean?
GLOTTIS noun- The opening between the true vocal cords, located in the larynx.