> As I understand it, "evangelical" just means the church tries to get more members

"Evangelical" is a label that was adopted by a specific group within Christian Protestantism that was reacting against specific elements that were seen as problematic within Fundamentalism (it was essentially a dissident offshoot of Fundamentalism) -- the term had some prior use, which in part inspired the label selected, but that's now pretty much its exclusive use when used to describe a subset of Christianity.

In some respects, some of those disagreements have faded over time; there's a lot of overlap in terms of both religious ideas and relation of religion to civil society between Fundamentalists and some subset of Evangelicals, though the range of Evangelical views is still broader. Its not uncommon for people outside of either movement to use "Evangelical" and "Fundamentalist" interchangeably.

"Evangelical" christianity has come to describe a certain group of mostly Protestant believers largely found in the South and Midwest US (https://en.wikipedia.org/wiki/Evangelicalism).

Interestingly enough, they're more of a political identity in some circles as beyond a few (relatively minor) theological differences with denominations like Baptists, Methodists, or "non-denominational" groups they mostly identify based on social/political issues (gay marriage, abortion, religion and government, etc. etc.) rather than theological ones (although they do their best to tie the two together).

"Evangelical" actually means something quite different from "evangelizing".

The "evangel" is the "eu-angel", the "good news", the "gospel". Or, more specifically, the gospels, the first four books of the New Testament.

To evangelize, to be "evangelistic", is to attempt to bring the "good news" to others. It's a matter of what you do.

To be "evangelical" is (so at least members of the groups that go by that name would say) to be grounded in the "good news", the gospels, the New Testament. (As opposed to, say, later church traditions.) It's a matter of what you believe and where those beliefs (purport to) come from.

The term "evangelical" has a complicated history, going back to Martin Luther and beyond. It's pretty much always denoted a strain of Protestantism, and in the modern-day US it means roughly "fundamentalist but not too fundamentalist". (On the other hand, in non-anglophone parts of Europe it mostly just means "Protestant".)

Evangelicals tend to be evangelistic, not least because the New Testament tells them to be. But you can be evangelistic without being evangelical; as you say, that would describe any church that tries to expand its membership, or any individual Christian who tries to persuade others to convert.