I used to think it meant pluralism, but I was wrong. Kevin gives a great, short overview in his blog, Hellbound? Here’s an excerpt:
In their commentary, Lifeway says that the view that people can find salvation through religions other than God, “… is generally called ‘universalism’ or ‘pluralism’ (though technically not the same thing, they are often used interchangeably and relate to one another). So, based on this data, Protestant pastors are overwhelmingly not pluralist/universalist.”
This statement is somewhat frustrating, because right after admitting that “universalism” and “pluralism” should not be used interchangeably, Lifeway uses them as synonyms in the very next sentence! So perhaps a bit of disambiguation is in order.
As Robin Parry and Christopher Partridge point out in the introduction to their excellent book Universal Salvation? The Current Debate, we can identify a typology of “universalisms,” at least one of which may actually be a synonym for pluralism. But Christian universalists rarely hold to such a belief. A brief summary of Parry and Partridge’s typology: