I am developing a website for a singer-songwriter. Among other sections, the website has a section for songs where the singer-songwriter has set his music on others’ poetry. (Unlike the majority of his songs where he is the author of both music and lyrics.) I look for a “keyword” that will mark this section in URLs, labels, directory names and other technical contexts, like http://www.example.com/songs/this_word/.
An appropriate English word is needed for I am worrying about both the visitors that will see this word in URLs and search engines that may stumble upon an inappropriate word.
Update. After receiving some helpful answers and comments, I came to a conclusion that actually I look for a word for “…on other people’s lyrics”, or “…on somebody else’s lyrics”. Important is not that a person is a composer (for the website’s visitors, he is by default), but that he is not the author of the lyrics (what is exceptional for this section only).