Dihydroergotamine is used to treat migraine headaches and cluster headaches. It is not recommended for migraines that affect only one side of the brain (hemiplegic migraine) or the base of the brain /neck area (basilar migraine), or to prevent migraines from occurring.
Pop music is an abbreviation for popular music. In other words, the main difference between pop music and alternative or underground music is the kind of following it has: pop music is usually known by a lot of people and regularly appears on TV.
Pop music is simply short for the term popular music. Meaning simply that a large # of people find a song or a music act enjoyable. Overall it was everyday people who made it so...a very long time ago. Either by singing the same song,buying the sheet music or seeing that act at a concert hall.