Upvote:1
The Encyclopedia Britannica article Reformed Church provides a short explanation on how (as the commenter said) the term "Reformed" was used by all Reformation churches, and how later on other groups like the Lutherans preferred another name:
Originally, all of the Reformation churches used this name (or the name Evangelical) to distinguish themselves from the βunreformed,β or unchanged, Roman Catholic church. After the great controversy among these churches over the Lordβs Supper (after 1529), the followers of Martin Luther began to use the name Lutheran as a specific name, and the name Reformed became associated with the Calvinistic churches (and also for a time with the Church of England). Eventually the name Presbyterian, which denotes the form of church polity used by most of the Reformed churches, was adopted by the Calvinistic churches of British background. The modern Reformed churches thus trace their origins to the Continental Calvinistic churches that retained the original designation.
Thus, it seems that the groups that use the name "Reformed" today still maintained the 16th century meaning:
Note: As I come up with more citations and more details on various angles relevant to the history of the term "Reformed", I'll continue to revise this answer.