It is primarily the full body of born again believers

It also can also refer to individual churches [gatherings of Christian believers].  However the word church can also be applied to unbelievers as well, since it's basic definition according to the Greek word is [{ecclesia} - a gathering of people together in one place in accord (assembly)].  The general picture of a modern or post modern Christian church often consists of a fancy building with; stained glass windows, an alter, a cross, a steeple, and pews, etc, etc, etc.  The word however does not refer to the early Christian church as being so lavishly adorned, in fact the place where they met to worship was often in individual believers homes - a simple and yet comforting atmosphere in the home is plenty adequate for fellowship and worship.  They met for public worship and teaching in the temple, and for private worship and fellowshipping in believers homes.  The word church generally refers to the believers bonded together for fellowshipping etc., and these believers are what consists of the true church, which is the body of Christ - each member being a part of his body, Christ being  the head of the church.   
 
Matt 16:18
18    And I say also unto thee, That thou art Peter, and upon this rock I will build my church; and the gates of hell shall not prevail against it.

Matt 18:15-17
15    Moreover if thy brother shall trespass against thee, go and tell him his fault between thee and him alone: if he shall hear thee, thou hast gained thy brother.
16    But if he will not hear thee, then take with thee one or two more, that in the mouth of two or three witnesses every word may be established.
17    And if he shall neglect to hear them, tell it unto the church: but if he neglect to hear the church, let him be unto thee as an heathen man and a publican.

Rom 16:3-5
3    Greet Priscilla and Aquila my helpers in Christ Jesus:
4    Who have for my life laid down their own necks: unto whom not only I give thanks, but also all the churches of the Gentiles.
5    Likewise greet the church that is in their house. Salute my wellbeloved Epaenetus, who is the firstfruits of Achaia unto Christ.

Acts 1:13-14
13    And when they were come in, they went up into an upper room [in their house], where abode both Peter, and James, and John, and Andrew, Philip, and Thomas, Bartholomew, and Matthew, James the son of Alphaeus, and Simon Zelotes, and Judas the brother of James.
14    These all continued with one accord in prayer and supplication, with the women, and Mary the mother of Jesus, and with his brethren.

Acts 2:46-47
46    And they, continuing daily with one accord in the temple, and breaking bread from house to house, did eat their meat with gladness and singleness of heart,
47    Praising God, and having favour with all the people. And the Lord added to the church daily such as should be saved.

Acts 5:11
11    And great fear came upon all the church, and upon as many as heard these things.

Acts 8:1
1    And Saul was consenting unto his death. And at that time there was a great persecution against the church which was at Jerusalem; and they were all scattered abroad throughout the regions of Judaea and Samaria, except the apostles.

Acts 8:3
3    As for Saul, he made havock of the church, entering into every house, and haling men and women committed them to prison.

Acts 9:11-17
11    And the Lord said unto him, Arise, and go into the street which is called Straight, and inquire in the house of Judas for one called Saul, of Tarsus: for, behold, he prayeth,
12    And hath seen in a vision a man named Ananias coming in, and putting his hand on him, that he might receive his sight.
13    Then Ananias answered, Lord, I have heard by many of this man, how much evil he hath done to thy saints at Jerusalem:
14    And here he hath authority from the chief priests to bind all that call on thy name.
15    But the Lord said unto him, Go thy way: for he is a chosen vessel unto me, to bear my name before the Gentiles, and kings, and the children of Israel:
16    For I will shew him how great things he must suffer for my name's sake.
17    And Ananias went his way, and entered into the house; and putting his hands on him said, Brother Saul, the Lord, even Jesus, that appeared unto thee in the way as thou camest, hath sent me, that thou mightest receive thy sight, and be filled with the Holy Ghost.

Acts 10:5-6
5    And now send men to Joppa, and call for one Simon, whose surname is Peter:
6    He lodgeth with one Simon a tanner, whose house is by the sea side: he shall tell thee what thou oughtest to do.

Acts 12:11-12
11    And when Peter was come to himself, he said, Now I know of a surety, that the Lord hath sent his angel, and hath delivered me out of the hand of Herod, and from all the expectation of the people of the Jews.
12    And when he had considered the thing, he came to the house of Mary the mother of John, whose surname was Mark; where many were gathered together praying.

Acts 14:27
27    And when they were come, and had gathered the church together, they rehearsed all that God had done with them, and how he had opened the door of faith unto the Gentiles.

Acts 16:40
40    And they went out of the prison, and entered into the house of Lydia: and when they had seen the brethren, they comforted them, and departed.

Acts 17:5
5    But the Jews which believed not, moved with envy, took unto them certain lewd fellows of the baser sort, and gathered a company, and set all the city on an uproar, and assaulted the house of Jason, and sought to bring them out to the people.

Acts 18:7
7    And he departed thence, and entered into a certain man's house, named Justus, one that worshipped God, whose house joined hard to the synagogue.

Acts 20:28
28    Take heed therefore unto yourselves, and to all the flock, over the which the Holy Ghost hath made you overseers, to feed the church of God, which he hath purchased with his own blood.

Acts 21:8
8    And the next day we that were of Paul's company departed, and came unto Caesarea: and we entered into the house of Philip the evangelist, which was one of the seven; and abode with him.

Acts 28:30-31
30    And Paul dwelt two whole years in his own hired house, and received all that came in unto him,
31    Preaching the kingdom of God, and teaching those things which concern the Lord Jesus Christ, with all confidence, no man forbidding him.

1 Cor 1:2
2    Unto the church of God which is at Corinth, to them that are sanctified in Christ Jesus, called to be saints, with all that in every place call upon the name of Jesus Christ our Lord, both theirs and ours:

1 Cor 4:17
17    For this cause have I sent unto you Timotheus, who is my beloved son, and faithful in the Lord, who shall bring you into remembrance of my ways which be in Christ, as I teach every where in every church.

1 Cor 12:28
28    And God hath set some in the church, first apostles, secondarily prophets, thirdly teachers, after that miracles, then gifts of healings, helps, governments, diversities of tongues.

1 Cor 14:4
4    He that speaketh in an unknown tongue edifieth himself; but he that prophesieth edifieth the church.

1 Cor 15:9
9    For I am the least of the apostles, that am not meet to be called an apostle, because I persecuted the church of God.

1 Cor 16:19
19    The churches of Asia salute you. Aquila and Priscilla salute you much in the Lord, with the church that is in their house.
20    All the brethren greet you. Greet ye one another with an holy kiss.

Eph 1:22
22    And hath put all things under his feet, and gave him to be the head over all things to the church,

Eph 5:23
23    For the husband is the head of the wife, even as Christ is the head of the church: and he is the saviour of the body.

Eph 5:27
27    That he might present it to himself a glorious church, not having spot, or wrinkle, or any such thing; but that it

Col 1:18
18    And he is the head of the body, the church: who is the beginning, the firstborn from the dead; that in all things he might have the preeminence.

Col 1:24
24    Who now rejoice in my sufferings for you, and fill up that which is behind of the afflictions of Christ in my flesh for his body's sake, which is the church:

Col 4:15
15    Salute the brethren which are in Laodicea, and Nymphas, and the church which is in his house.

1 Tim 3:15
15    But if I tarry long, that thou mayest know how thou oughtest to behave thyself in the house of God, which is the church of the living God, the pillar and ground of the truth.

Phile 1:2
2    And to our beloved Apphia, and Archippus our fellowsoldier, and to the church in thy house:

James 5:14
14    Is any sick among you? let him call for the elders of the church; and let them pray over him, anointing him with oil in the name of the Lord:

All of these above verses refer to the church in various ways; sometimes as church held in the home, sometimes no clear description was given concerning where the church was held, sometimes in the temple, and sometimes as the body of Christ - which includes all Christians [born again believers].