Holman Bible Dictionary 
According to the Greek historian Herodotus, a Scythian attack forced the Medes to withdraw from an assault against Nineveh (apparently 626-620 B.C.). Later, the Scynthians advanced southward along the Palestinian coast to the Egyptian border (611 B.C.), where they were bought off by the Egyptian Pharaoh. They were eventually driven back northward into southern Russia by the Medes.
Scythian power was dominant in the area northwest of the Black Sea until about 350 B.C. Eventually, new invaders, the Sarmatians, having confined them to the Crimean area, destroyed the remaining Scythian remnants after A.D. 100.
The Old Testament refers to Scythians as Ashchenaz ( Genesis 10:3; Jeremiah 51:27 ). See Ashchenaz . Earlier scholars identified the Scythians as Jeremiah's foe from the north and Zephaniah's threatened invader of Judah, but such theories rest on weak evidence. Colossians 3:11 uses Scythians to represent the most repugnant barbarian and slave, saying they, too, are accepted in Christ, all social and cultural barriers being abolished in His church.
Hastings' Dictionary of the Bible 
SCYTHIANS . A wandering race of the Indo-European stock who lived between the Danube and the Don, and spread over the territory between the Caucasus and the Caspian. They were a cruel and savage people, of huge build. The Athenians employed them as police. In Colossians 3:11 they are mentioned as a degree worse than barbarians. The latter word simply connoted those who spoke neither Greek nor Latin.
American Tract Society Bible Dictionary 
Wandering tribes in the immense regions north and northeast of the Black and Caspian Seas. They are said by Herodotus to have made an incursion into Southwestern Asia and Egypt, some seven hundred years before Christ; and it was perhaps a fragment of this host, located at Bethshean, which gave that city its classical name Scythopolis. In Colossians 3:11 , "Scythian" appears to signify the rudest of barbarians.
International Standard Bible Encyclopedia 
sith´i - anz ( οἱ Σκύθαι , hoi Skúthai ): The word does not occur in the Hebrew of the Old Testament, but Septuagint of Judges 1:27 inserts ( Σκυθῶν πόλις , Skuthṓn pólis (Scythopolis), in explanation, as being the same as Beth-shean. The same occurs in Apocrypha (Judith 3:10; 1 Macc 12:29), and the Scythians as a people in 2 Macc 4:47, and the adjective in 3 Macc 7:5. The people are also mentioned in the New Testament ( Colossians 3:11 ), where, as in Maccabees, the fact that they were barbarians is implied. This is clearly set forth in classical writers, and the description of them given by Herodotus in book iv of his history represents a race of savages, inhabiting a region of rather indefinite boundaries, north of the Black and Caspian seas and the Caucasus Mountains. They were nomads who neither plowed nor sowed (iv. 19), moving about in wagons and carrying their dwellings with them (ibid. 46); they had the most filthy habits and never washed in water (ibid. 75); they drank the blood of the first enemy killed in battle, and made napkins of the scalps and drinking bowls of the skulls of the slain (ibid. 64-65). Their deities were many of them identified with those of the Greeks, but the most characteristic rite was the worship of the naked sword (ibid. 62), and they sacrificed every hundredth man taken in war to this deity. War was their chief business, and they were a terrible scourge to the nations of Western Asia. They broke through the barrier of the Caucasus in 632 Bc and swept down like a swarm of locusts upon Media and Assyria, turning the fruitful fields into a desert; pushing across Mesopotamia, they ravaged Syria and were about to invade Egypt when Psammitichus I, who was besieging Ashdod, bought them off by rich gifts, but they remained in Western Asia for 28 years, according to Herodotus. It is supposed that a company of them settled in Beth-shean, and from this circumstance it received the name Scythopolis. Various branches of the race appeared at different times, among the most noted of which were the Parthians (which see).
The Nuttall Encyclopedia 
The name of a people of various tribes that occupied the steppes of SE. of Europe and W. of Asia adjoining eastward, were of nomadic habit; kept herds of cattle and horses, and were mostly in a semi-savage state beyond the pale of civilisation; the region they occupied is called Scythia.