YOUR QUESTION (No. 51)
In Matt 18:17 what is Jesus referring to
when he says the word 'church?'
Jesus did not actually utter the word, "church." The Greek that he uttered is ekklesia (a called out assembly), that in English is generally rendered "church" even though church comes from a different Greek word, kuriokos, that means "house of a lord." Here is the text in question:
 If he refuses to listen to them, tell it to the church; and if he refuses to listen even to the church, let him be to you as a Gentile and a tax collector.
I have written an article that is the answer to your question, http://www.voiceofjesus.org/ekklesia.html. His use of 'ekklesia' in Matthew 18:17 refers to the synagogue, as one can easily determine from the context with its reference to "Gentile" and "tax collector." Only once more in the Gospels did he utter this word:
 And I tell you, you are Peter, and on this rock I will build my church, and the powers of death shall not prevail against it.
Simply put, he means the assembly of those who will stand before him, at the Last Judgment, of the children of the Father that he has called out of this world. It is one single assembly that he is building, and he is calling it out from the world and gathering it even today.
Matt.25Christians with their countless "churches" have completely missed the mark.