From BiblePortal Wikipedia

Vine's Expository Dictionary of NT Words [1]

1: Φυλακή (Strong'S #5438 — Noun Feminine — phulake — foo-lak-ay' )

from phulasso, "to guard," denotes (a) "a watching, keeping watch,"  Luke 2:8; (b) "persons keeping watch, a guard,"  Acts 12:10; (c) "a period during which watch is kept," e.g.,  Matthew 24:43; (d) "a prison, a hold." In  Revelation 18:2 , AV, Babylon is described figuratively, first as a "hold" and then as a "cage" of every unclean and hateful bird (RV, "hold" in both clauses; marg., "prison"). The word is almost invariably translated "prison." See Hold , Imprisonment Prison , Ward , Watch.

Webster's Dictionary [2]

(1): (n.) An outer framework of timber, inclosing something within it; as, the cage of a staircase.

(2): (n.) The box, bucket, or inclosed platform of a lift or elevator; a cagelike structure moving in a shaft.

(3): (n.) A skeleton frame to limit the motion of a loose piece, as a ball valve.

(4): (v. i.) To confine in, or as in, a cage; to shut up or confine.

(5): (n.) The catcher's wire mask.

(6): (n.) The drum on which the rope is wound in a hoisting whim.

(7): (n.) A box or inclosure, wholly or partly of openwork, in wood or metal, used for confining birds or other animals.

(8): (n.) A place of confinement for malefactors

(9): (n.) A wirework strainer, used in connection with pumps and pipes.

Hastings' Dictionary of the Bible [3]

CAGE . Birds were taken to market in a cage or coop of wicker work (  Jeremiah 5:27 ); a similar cage might hold a decoy-bird in fowling ( Sir 11:30 ). One of Ashurbanipal’s hunting scenes shows a cage of strong wooden bars from which a lion is being let loose (cf.   Ezekiel 19:8 RV [Note: Revised Version.] ). In   Revelation 18:2 render, with RV [Note: Revised Version.] , ‘hold’ or ‘prison’ for AV [Note: Authorized Version.] ‘cage.’

A. R. S. Kennedy.

Wilson's Dictionary of Bible Types [4]

 Jeremiah 5:27 (b) This is a name given to a home, synagogue, or temple where Satan's deceits are housed and protected, as the church building of a cult which is anti-Christian.

 Revelation 18:2 (a) It reveals that there are religious systems which house Satanic forces and hold them in such a grip that no Gospel and no emancipating power from Heaven is permitted to enter and deliver.

Morrish Bible Dictionary [5]

It is said symbolically that as a cage or trap is full of birds, so the houses of the Jews were full of deceit.  Jeremiah 5:27 . 'A cage of every unclean and hateful bird,' is a character of mystical Babylon.  Revelation 18:2 . The word here is φυλακή,often translated 'prison.'

Smith's Bible Dictionary [6]

Cage. The term so rendered in  Jeremiah 5:27, is more properly, a trap in which decoy birds were placed. In  Revelation 18:2, the Greek term means A Prison.

Fausset's Bible Dictionary [7]

( Jeremiah 5:27), rather "a trap" with decoy birds in it. In  Revelation 18:2 a prison, guardhouse. (See Bird .)

Easton's Bible Dictionary [8]

 Jeremiah 5:27 Amos 8:1 Revelation 18:2 Phulake

King James Dictionary [9]

CAGE, To confine in a cage to shut up, or confine.

Cyclopedia of Biblical, Theological and Ecclesiastical Literature [10]

( כְּלוּב , Kelub', Φυλακή ). Bird-cages are named in  Jeremiah 5:27; Revelation 18:2; and are perhaps implied in  Job 41:5, where "playing with a bird' is mentioned. (See Bird). In the first of these passages the Sept. renders it by Παγίς , a Snare, implying that it was used for holding decoys with which to entrap other birds until the cage was full an idea which the derivation of the Hebrews word confirms (from כָּלִב , to Clasp together by the shutting of the valves or trap). This interpretation is therefore better than that of the margin, "coop," or that of the Talmud, "a place of fattening," implying that it was used for holding wild or tame fowls until they became fit for the table. The same article is referred to in  Sirach 11:30, under the term Κάρταλλος , which is elsewhere used of a tapering basket. (See Fowling). In  Revelation 18:2, the Greek term is Φυλακή , meaning a prison or restricted habitation rather than a cage. This just suffices to show that the ancient Israelites kept birds in cages; but we have no farther information on the subject, nor any allusions to the singing of birds so kept. The cages were probably of the same forms which we still observe in the East, and which are shown in the annexed engraving. It is remarkable that there is no appearance of bird-cages in any of the domestic scenes which are portrayed on the mural tablets of the Egyptians. In  Amos 8:12, the same word Kelub' denotes a fruit-basket, so called, doubtless, from its resemblance toa cage. (See Basket).

International Standard Bible Encyclopedia [11]

kāj ( כּלוּב , kelūbh  ; φυλακή , phulakḗ ): The earliest known form of cage made to confine a bird, for the pleasure of its song or the beauty of its coloring, was a crude affair of willows or other pliable twigs. Later cages were made of pottery, and now they are mostly made of wire. References in the Bible make it very clear that people were accustomed to confine in cages such birds as they especially prized for pets, or to detain them for market purposes. James indicated that cages were common when he wrote ( James 3:7 ): "For every kind of beasts and birds ... is tamed, and hath been tamed by mankind." In Job ( Job 41:5 ) we find these lines

"Wilt thou play with him as with a bird?

Or wilt thou bind him for thy maidens?"

The only way to play with a bird is to confine it so that it grows accustomed to you and Thus loses fear. Jeremiah compared the civil state of Judah to a "cage (crate) full of birds" ( Jeremiah 5:27 ), "the houses of the rich being stuffed with craftily-obtained wealth and articles of luxury" ( HDB ). The sale of sparrows as an article of food still continues in the eastern markets. Jesus referred to this ( Matthew 10:29 ) and it was He who entered the temple and overthrew "the seats of them that sold the doves" ( Matthew 21:12 ). In  Revelation 18:2 we find a reference to "a hold (the King James Version "cage") of every unclean and hateful bird." See also Ecclesiasticus 11:30.