From BiblePortal Wikipedia

Webster's Dictionary [1]

(1): ( n.) A light, volatile, mobile, inflammable liquid, (C2H5)2O, of a characteristic aromatic odor, obtained by the distillation of alcohol with sulphuric acid, and hence called also sulphuric ether. It is powerful solvent of fats, resins, and pyroxylin, but finds its chief use as an anaesthetic. Called also ethyl oxide.

(2): ( n.) Any similar oxide of hydrocarbon radicals; as, amyl ether; valeric ether.

(3): ( n.) Supposed matter above the air; the air itself.

(4): ( n.) A medium of great elasticity and extreme tenuity, supposed to pervade all space, the interior of solid bodies not excepted, and to be the medium of transmission of light and heat; hence often called luminiferous ether.

King James Dictionary [2]

E'THER, n. L. oether Gr. to burn, to shine Eng. weather.

1. A thin, subtil matter, much finer and rarer than air, which, some philosophers suppose, begins from the limits of the atmosphere and occupies the heavenly space.

There fields of light and liquid ether flow.

2. In chimistry, a very light, volatile and inflammable fluid, produced by the distillation of alcohol or rectified spirit of wine, with an acid. It is lighter than alcohol, of a strong sweet smell, susceptible of great expansion, and of a pungent taste. It is so volatile, that when shaken it is dissipated in an instant.

Fausset's Bible Dictionary [3]

A city in the Shephelah or low country of Judah; allotted to Simeon ( Joshua 15:42;  Joshua 19:7). JOCHEN in  1 Chronicles 4:32. In the wilderness country below Hebron, E. of Beersheba. Tel Athar now, according to Van de Velde.

Smith's Bible Dictionary [4]

E'ther. (Abundance). One of the cities of Judah, in the low country, the Shefelah ,  Joshua 15:42, allotted to Simeon.  Joshua 19:7.

Hastings' Dictionary of the Bible [5]

Ether (  Joshua 15:42;   Joshua 19:7 ). A town of Judah noticed with Libnah, apparently near the plain of Philistia, given to Simeon, and near Rimmon. The site is unknown.

Holman Bible Dictionary [6]

 Joshua 15:42 2 Joshua 19:7

Morrish Bible Dictionary [7]

City of Judah, allotted to Simeon.  Joshua 15:42;  Joshua 19:7 .

Cyclopedia of Biblical, Theological and Ecclesiastical Literature [8]

(Hebrews id. עֵתֶר , Abundance), one of the cities in the plain (Shephelah) of Judah (mentioned between Libnah and Ashan,  Joshua 15:42, Sept. ῎Αθερ v.r. Ι᾿Θάκ ) , eventually assigned to Simeon (mentioned between Remmon and Ashan,  Joshua 19:7, Sept. ῎Αθερ v.r. Ι᾿Εθέρ ). In the parallel list of the towns of Simeon in  1 Chronicles 4:32, Tochen is substituted for Ether. In the Onomasticon Eusebius and Jerome mention it twice (s.v. Ε᾿Θέρ , Ether; Ι᾿Εθέρ , Jether in the latter case confounding it with Jattir a city of priests, which contained friends of David during his troubles under Saul), and state that it was then a considerable place ( Κώμη Μεγίστη ) , retaining the name of Jethira ( Ι᾿Εθειρά , Ι᾿Εθαρά ) , very near Malatha, in the interior of the district of Daroma, that is, in the desert country below Hebron and to the east of Beersheba. At Beit-Jibrin Van de Velde heard of a Tell Athar in this neighborhood, but could not learn its distance or direction (Memoir, page 311). For the present, we may conjecturally place it at Beit-Auwa, in the vicinity of the associated localities, S. of Beit-Jibrin and W. of Hebron; a ruined village, covering low hills on both sides of the path, and exhibiting foundations of hewn stones, leading to the inference that it was once an extensive town (Robinson, Researches, 3:10).

International Standard Bible Encyclopedia [9]

ē´thẽr ( עתר , ‛ether  ; Ἀθέρ , Athér ): A town in Judah ( Joshua 15:42 ), near Libnah, assigned to Simeon ( Joshua 19:7 ). Kḣ el ‛Atr (identical in spelling with Ether) is possibly the site. It is near Beit Jibrı̂n and is described as "an ancient site: cisterns, foundations, quarried rock and terraces" ( PEF , III, 261, 279).

The Nuttall Encyclopedia [10]

A volatic liquid prepared from the distillation of alcohol and sulphuric acid at high temperature; is colourless, and emits a sweet, penetrating odour; is highly combustible; a useful solvent, and an important anæsthetic.