King James Bible Dictionary

Frequently mentioned in Scripture. It is called in Hebrew maphteah, i.e., the opener (Judges 3:25); and in the Greek New Testament kleis, from its use in shutting (Matthew 16:19; Luke 11:52; Revelation 1:18, etc.). Figures of ancient Egyptian keys are frequently found on the monuments, also of Assyrian locks and keys of wood, and of a large size (comp. Isaiah 22:22).

The word is used figuratively of power or authority or office (Isaiah 22:22; Revelation 3:7; Revelation 1:8; comp. 9:1; 20:1; comp. also Matthew 16:19; 18:18). The "key of knowledge" (Luke 11:52; comp. Matthew 23:13) is the means of attaining the knowledge regarding the kingdom of God. The "power of the keys" is a phrase in general use to denote the extent of ecclesiastical authority.

General references
Judges 3:25

A symbol of authority
Isaiah 22:22; Matthew 16:19; Revelation 1:18; Revelation 3:7; Revelation 9:1; Revelation 20:1

Figurative
Luke 11:52

The key of a native Oriental lock is a piece of wood, from seven inches to two feet in length, fitted with the wires or short nails, which, being inserted laterally into the hollow bolt which serves as a lock, raises other pins within the staple so as to allow the bolt to be drawn back. (Keys were sometimes of bronze or iron, and so large that one was as much as a man could carry. They are used in Scripture as a symbol of authority and power. Giving keys to a person signifies the intrusting of him with an important charge. (Matthew 16:19) In England in modern times certain officers of the government receive, at their induction into office, a golden key.

ED.)

KEY, noun ke. In a general sense, a fastener; that which fastens; as a piece of wood in the frame of a building, or in a chain, etc.

1. An instrument for shutting or opening a lock, by pushing the bolt one way or the other. Keys are of various forms, and fitted to the wards of the locks to which they belong.

2. An instrument by which something is screwed or turned; as the key of a watch or other chronometer.

3. The stone which binds an arch. [See Key-stone.]

4. In an organ or harpsichord, the key or finger key is a little lever or piece in the fore part by which the instrument is played on by the fingers.

5. In music, the key or key note, is the fundamental note or tone, to which the whole piece is accommodated, and with which it usually begins and always ends. There are two keys, one of the major, and one of the minor mode. key sometimes signifies a scale or system of intervals.

6. An index, or that which serves to explain a cypher. Hence,

7. That which serves to explain any thing difficult to be understood.

8. In the Romish church, ecclesiastical jurisdiction, or the power of the pope, or the power of excommunicating or absolving.

9. A ledge or lay of ricks near the surface of the water.

10. The husk containing the seed of an ash.

KEY, noun A bank or wharf built on the side of a river or harbor, for the convenience of loading and unloading ships, and securing them in their stations. Hence keys are furnished with posts, rings, cranes, capstans, etc. It is sometimes written quay.