Mash-up is a term used to describe the combination of two or more distinct elements into a single entity. It is often used in the context of music, where two or more songs are blended together to create a new song. The term can also be used to describe the combination of two or more different styles of art, literature, or other media. In the context of crosswords, the solutions for the term mash-up are 'AMALGAM' and 'FUSION'. AMALGAM is a noun that refers to a combination of different elements, while FUSION is a noun that refers to the process of combining two or more things into one.