Anything ecclesial is related to a Christian church. You might go to Sunday services with your friend to find out what ecclesial offerings his church has.
The adjective ecclesial derives from the Greek ekklesiastes, "speaker in a church" and its root ekkalein, "to call out." It's specifically used to talk about the Christian religion. If someone mentions ecclesial institutions, they mean churches, and a reference to an ecclesial service is the same as talking about a sermon in a Christian church. Catholics sometimes use the phrase "ecclesial community" to refer to non-Catholic churches.