Evangelium is latin for Gospel. In old English Gospel is God Spiel, or good word (Good News)
Evanglicals of the Baptist stripe claim that only the Bible, (those books they accept) and in some cases only the version they accept can be used to determine the truth. No historical context, only what the Holy Spirit tells them individually.
Among the Evangelical Lutherans (and James can corret me if I’m off base) it was to signify a return to the Bible as the basis for the Faith, and a return to what Lutherans saw as a return to the practice of the Early Church as they saw it.
There are Non-Roman Catholics who call themselves Evangelical Catholic, they are not in communion with Rome, and decide on their own what they will retain from Catholic teachings and morals, and what they will reject. Most are modern day schisms from the Old Catholic Church of Utrech, in the Netherlands.
Lastly there are Catholics in communion with Rome who call themselves Evangelical, because the Catholic Church teaches that we are the Church found in the Gospels, the same today as in the days of the Apostles. Catholics also practice what are called in the Church, Evangelical Counsels, or Faith Love and Hope. (Other Christians also refer to these as they are taught in the Gospels.)