Smith's Bible Dictionary 
Plains. This one term does duty, in the Authorized Version, for no less than eight distinct Hebrew words.
1. Abel . (Meadow). This word perhaps answers more nearly to our word, "Meadow" than any other. It occurs in the names of Abel-maim Abel-meholah, Abel-shittim and is rendered "plain" in Judges 11:33 - "plain of vineyards." See Abel, 2 .
2. Bik'ah or Bik'a . (To Cleave, A Valley). Fortunately, we are able to identify the most remarkable of the bik'ahs of the Bible, and thus, to ascertain the force of the term. The great plain or valley of Coele-Syria, the "Hollow Land" of the Greeks, which separates the two ranges of Lebanon and Anti-Lebanon, is the most remarkable of them all. Out of Palestine, we find denoted by the word, bik'ah , the "plain of the land of Shiner," Genesis 11:2, the "plain of Mesopotamia," Ezekiel 3:22-23; Ezekiel 8:4; Ezekiel 37:1-2, and the "plain in the province of Dura." Daniel 3:1.
3. Ha arabah . (Dry Region). The peculiar name of the valley of the Jordan.
4. Hak kikkar . (Ciccar), (To Move In A Circle, As A Coin or A Loaf). The plain around Jericho. Genesis 13:10).
5. Ham mishor . (Oven Place, Plain). In Deuteronomy 3:10, it refers to the region now called El Belka , the high level table-lands, (of Moab), east of the Dead Sea.
6. Ha shefelah . (A Low Plain). The invariable designation of the depressed, flat or gently-undulating region which intervened between the highlands of Judah and the Mediterranean, and was commonly in possession of the Philistines.
7. Elon . (Oak, or Grove Of Oaks). Our translators have uniformly rendered this word "plain;" but this is not the verdict of the majority or the most trustworthy of the ancient versions. They regard the word as meaning an "Oak" or "Grove Of Oaks", a rendering supported by nearly all the commentators and lexicographers of the present day. The passages in which the word occurs erroneously translated "plain" are as follows: plain [oak or grove] of Moreh, Genesis 12:6; Genesis 11:30, plain [oak grove] of Mamre, Genesis 13:18; Genesis 14:13; Genesis 18:1, plain [grove of the wanderers] of Zaanaim, "wanders", Judges 4:11, plain [oak of the covenant, or monumental oak] of the pillar, Judges 9:6, plain [grove] of Meonenim, "Magicians" , Judges 9:37, plain [oak or grove] of Tabor, 1 Samuel 10:5.
8. Emek . (Valley). As applied to the Plain of Esdraelon and other valleys or plains, as Achor, Ajalon, Baca, Berachah, Bethrehob, Elah, Gibeon, Hebron, Jehoshaphat, Keziz, Rephaim, Shaveh, Siddim, and Succoth, besides the valley of "decision" in Joel 3:14.
Fausset's Bible Dictionary 
abel ("meadow"; compare ABEL MEHOLAH.) Βiqu'ah , the great, plain Coele ("hollow") Syria between Lebanon and Antilebanon; Βikath Αven , Amos 1:5; "the valley (Βiqa'ath ) of Lebanon" ( Joshua 11:17; Joshua 12:7), Βiqua'ath Μizpeh ( Joshua 11:8); still called El Bekaa , 60 miles long, five broad. Also 2 Chronicles 35:22; Genesis 11:2; Nehemiah 6:2; Daniel 3:1. Ηac Ciccar , the region round about the Jordan valley ( Genesis 13:10; Genesis 19:17; Genesis 19:25-29). Ηam Μishor ( Deuteronomy 3:10; Deuteronomy 4:43), the smooth (from yaashar , "straight") downs of Moab stretching from Jordan E. of Jericho into the Arabian desert, contrasting with the rugged country W. of Jordan and with the higher lands of Bashan and Argob.
The Belka pasture, regular in its undulations, good in its turf ( 2 Chronicles 26:10). Ηa 'Αrabah , the Jordan valley and its continuation S. of the Dead Sea. Ηa shephelah , the undulating, rolling, "low hills" between the mountainous part of Judah and the coast plain of the Mediterranean ( Deuteronomy 1:7, "the vale"; 2 Chronicles 28:18, "the low country"); Seville in Spain is derived from it. 'Εlon ought to be translated "oak" or "oaks" ( Genesis 12:6; Genesis 13:18; Judges 4:11; Judges 9:6; Judges 9:37; 1 Samuel 10:3). Emek the valley of Jezreel (Esdraelon), the eastern part, Megiddo the western part, of the one plain.