Found most often in Matthew-Acts, but also used in 1 Cor. 16:9; 2 Cor. 2:12; Col. 4:3; Jas. 5:9; Rev. 3:8, 20; 4:1, the Greek noun “thura” meant “door,” “entrance,” “gate.”  Sometimes this word is used figuratively to mean “at hand” (Mt. 24:33).  In Acts 5:19, this word describes prison doors.  Paul said God can open doors for His people (Col. 4:3).