The most common and most likely answer to this crossword clue is the 7 letter word CARIOCA
I've seen this crossword clue in The Sunday Telegraph
C
A
R
I
O
C
A
More clues leading to the result CARIOCA
Buddy explains!
The straight part
We know that "Dance music a Rio carnival includes" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case dance music a rio carnival includes = carioca.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 CARIOCA mean?
CARIOCA noun- An inhabitant of Rio de Janeiro.
- A sideways step in which one leg crosses over the other.