Does it refer to a building or more than that?
The word "church" is from the New Testament Greek word "Ekkesia". From this word, we get the English word Ecclesiastical meaning "of the church". In Spanish, the word iglesia, and in French, eglise, both meaning "church" comes from the same Greek word, Ekklesia. As far as I know only one denomination, the Christadelphians, the sponsors of this website, use the word Ekklesia instead of church to describe their congregations. We spell it Ecclesia. The word applies to the congregation of Christians in a particular place or as an overall whole but never does it apply to a building the way we often apply the word "church" in English.
Ekklesia is composed of two Greek words: Ek = "out of"; and "klesis" = "calling". The word Ekklesia therefore means an assembly of "called out ones". Called out of where? Called out of the world to be God's children.
2 Corinthians 6:17,18 Wherefore come out from among them, and be ye separate, saith the Lord, and touch not the unclean thing; and I will receive you, 18 And will be a Father unto you, and ye shall be my sons and daughters, saith the Lord Almighty.
I hope you have found this helpful.