Chamber music and Classical music

Chamber music noun - Serious music performed by a small group of musicians.

Classical music and chamber music are semantically related In some cases you can use "Classical music" instead a noun phrase "Chamber music".

Classical music noun - Traditional genre of music conforming to an established form and appealing to critical interest and developed musical taste.

Chamber music and classical music are semantically related in serious music topic. You can use "Chamber music" instead a noun phrase "Classical music".