The most common and most likely answer to this crossword clue is the 7 plus 6 letter word GRAPHIC DESIGN
I've seen this crossword clue in The Daily Telegraph
G
R
A
P
H
I
C
D
E
S
I
G
N
More clues leading to the result GRAPHIC DESIGN
Buddy explains!

The straight part
We know that "part of magazine" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case part of magazine = graphic design.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.