Strong's #2374: thura (pronounced thoo'-rah)
 apparently a primary word (compare "door"); a portal or entrance (the opening or the closure, literally or figuratively):--door, gate.
Thayer's Greek Lexicon:
 ́ 
 
  thura 
 
 1) a door
 
 1a) the vestibule
 1b) used of any opening like a door, an entrance, way or passage into
 1c) in a parable or metaphor
 
 1c1) the door through which sheep go in and out, the name of him who brings salvation to those who follow his guidance
 1c2) "an open door" is used of the opportunity of doing something
 1c3) the door of the kingdom of heaven (likened to a palace) denotes the conditions which must be complied with in order to be received into the kingdom of God
 
  Part of Speech: noun feminine
Relation: apparently a root word [compare "door" ]
  Citing in TDNT: 3:173, 340
 
Usage:
This word is used 40 times:
Matthew 6:6: "and when thou hast shut thy  door, pray to thy Father which"
Matthew 24:33: "it is near, even at  the doors."
Matthew 25:10: "marriage: and the  door was shut."
Matthew 27:60: "a great stone to the  door of the sepulcher, and departed."
Matthew 28:2: "stone from the  door, and sat upon it."
Mark 1:33: "gathered together at the  door."
Mark 2:2: "there was no room to receive them, no, not so much as about the  door: and he preached the"
Mark 11:4: "tied by the  door without in a place where two ways met; and"
Mark 13:29: "it is nigh, even at  the doors."
Mark 15:46: "rolled a stone unto the  door of the sepulcher."
Mark 16:3: "the stone from the  door of the sepulcher?"
Luke 11:7: "and say, Trouble me not: the  door is now"
Luke 13:25: "master of the house is risen up, and hath shut to the  door, and ye begin"
Luke 13:25: "to stand without, and to knock at the  door, saying, Lord,"
John 10:1: "not by the  door into the sheepfold,"
John 10:2: "he that entereth in by the  door is the shepherd of the"
John 10:7: "I am the  door of the sheep."
John 10:9: "I am the  door: by me if any man"
John 18:16: "stood at the  door without. Then went out that other"
John 20:19: "week, when the  doors were shut where the disciples"
John 20:26: "then came Jesus, the  doors being shut, and stood in"
Acts 3:2: "daily at the  gate of the temple which is called"
Acts 5:9: "husband are at the  door, and shall carry thee out."
Acts 5:19: "opened the prison  doors, and brought them forth, and said,"
Acts 5:23: "without before the  doors: but when we had opened, we found no man"
Acts 12:6: "and the keepers before the"
Acts 12:6: "and the keepers before the"
Acts 12:13: "as Peter knocked at the  door of the gate, a damsel came"
Acts 14:27: "with them, and how he had opened  the door of faith unto the"
Acts 16:26: "immediately all the  doors were opened, and every one's bands"
Acts 16:27: "and seeing the prison  doors open, he drew out his sword,"
Acts 21:30: "temple: and forthwith the  doors were shut."
1 Corinthians 16:9: "For a great  door and effectual is opened unto me, and"
2 Corinthians 2:12: "preach Christ's gospel, and  a door was opened unto me of the Lord,"
Colossians 4:3: "God would open unto us  a door of utterance, to speak the mystery"
James 5:9: "judge standeth before the  door."
Revelation 3:8: "before thee an open  door, and no man can shut"
Revelation 3:20: "I stand at the  door, and knock: if any man"
Revelation 3:20: "and open the  door, I will come in to him, and"
Revelation 4:1: "I looked, and, behold,  a door was opened in heaven: and"