The most common and most likely answer to this crossword clue is the 9 letter word EARPIECES
I've seen this crossword clue in Financial Times
E
A
R
P
I
E
C
E
S
More clues leading to the result EARPIECES
Buddy explains!
The straight part
We know that "Parts attached to side of head" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case parts attached to side of head = earpieces.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 EARPIECES mean?
EARPIECES noun- A speaker placed inside or held near to the ear.
- A receiver of a telephone to hold near to your ear.
- The arm on a pair of glasses that hooks over the ear to hold them in place.