Question

1. He preferred jazz to rock music.
2. He preferred jazz music to rock music.
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Does #1 mean #2? Is 'music' missing after 'jazz' in #1?

Answer 1

Since "jazz" obviously is music, the two sentences are the same. However, the redundancy in 2 makes 1 the better sentence.

Answer 2

Yes, they both mean the same thing. Jazz is a genre of music, so it need not be stated as in "jazz music" in relation to "rock music". Using the word "music" once is enough in this sentence, although it's fine to use it twice as in the second sentence.