At its core this word does one thing: it takes something closed and makes it open. The New Testament uses it for the plainest of acts, opening a door, a gate, a tomb, a treasure chest, the mouth, the eyes, and then leans on each of those pictures to say something larger.
Two of its pictures became settled turns of phrase. To open the mouth is often more than parting the lips: it announces that someone is about to make a deliberate, weighty speech, so the act of opening signals the beginning of teaching, testimony, or prophecy. To open a door, likewise, can mean to make an opportunity available, room to preach or to act that only God can grant.
The word also carries the language of revelation and access. Heaven opens, the temple opens, sealed scrolls and the books of judgment are opened: in each case something hidden is laid bare and a barrier between God and people is taken down. The healing of the blind, where eyes are opened, sits at the hinge of the literal and the figurative, since restored sight in the Gospels keeps pointing past the body to spiritual perception.
Nuances
1ato open a door, gate, entrance, or container
Mat 2:11Mat 25:11Luk 12:36Luk 13:25Act 5:19Act 5:23Act 12:10Act 12:14Act 12:16Act 16:26Act 16:27Rev 3:8
1bto open the eyes: to give or restore sight, the healing of the blind
Mat 9:30Mat 20:33Jhn 9:10Jhn 9:14Jhn 9:17Jhn 9:21Jhn 9:26Jhn 9:30Jhn 9:32Jhn 10:21Jhn 11:37Act 9:40*
1cto open the mouth to begin a deliberate, weighty utterance, teaching, testimony, or prophecy
Mat 5:2Mat 13:35Act 8:35Act 10:34Act 18:142Co 6:11
1dto open the mouth or ears as a plain bodily act, of a person, an animal, or even the earth
Mat 17:27Mrk 7:35*Luk 1:64Rev 12:16Rev 13:6
1eto open the heavens, the temple, or a place of God's presence, so that what is hidden is revealed
Mat 3:16Luk 3:21Jhn 1:51Act 10:11Rev 4:1Rev 11:19Rev 15:5Rev 19:11
1fto open a scroll, book, or sealed thing, breaking it open so its contents take effect
Rev 5:2Rev 5:3Rev 5:4Rev 5:5Rev 5:9Rev 6:1Rev 6:3Rev 6:5Rev 6:7Rev 6:9Rev 6:12Rev 8:1
1gto open a way or opportunity, especially a door for the gospel that God alone grants
Act 14:271Co 16:92Co 2:12Col 4:3
1hto open what was shut or sealed so that what is inside is released, an opened tomb that gives up the dead or an opened shaft that releases what was confined
Mat 27:52Rev 3:7 (3×)Rev 9:2*
1ito open absolutely, used without a stated object: to grant entry or access in answer to a request
Mat 7:7Mat 7:8Luk 11:9Luk 11:10Jhn 10:3Act 8:32*Act 26:18*