(barn, corn, threshing- )floor, (threshing-, void) place

“Threshing” From Boyd’s Bible Dictionary:

(thrashing). Done anciently by treading with oxen or horses, or by drawn sleds, sometimes spiked, on earthen floors, usually on high spots of ground (Deut. 25:44Thou shalt not muzzle the ox when he treadeth out the corn. (Deuteronomy 25:4); 1 Chron. 21:15-2815And God sent an angel unto Jerusalem to destroy it: and as he was destroying, the Lord beheld, and he repented him of the evil, and said to the angel that destroyed, It is enough, stay now thine hand. And the angel of the Lord stood by the threshingfloor of Ornan the Jebusite. 16And David lifted up his eyes, and saw the angel of the Lord stand between the earth and the heaven, having a drawn sword in his hand stretched out over Jerusalem. Then David and the elders of Israel, who were clothed in sackcloth, fell upon their faces. 17And David said unto God, Is it not I that commanded the people to be numbered? even I it is that have sinned and done evil indeed; but as for these sheep, what have they done? let thine hand, I pray thee, O Lord my God, be on me, and on my father's house; but not on thy people, that they should be plagued. 18Then the angel of the Lord commanded Gad to say to David, that David should go up, and set up an altar unto the Lord in the threshingfloor of Ornan the Jebusite. 19And David went up at the saying of Gad, which he spake in the name of the Lord. 20And Ornan turned back, and saw the angel; and his four sons with him hid themselves. Now Ornan was threshing wheat. 21And as David came to Ornan, Ornan looked and saw David, and went out of the threshingfloor, and bowed himself to David with his face to the ground. 22Then David said to Ornan, Grant me the place of this threshingfloor, that I may build an altar therein unto the Lord: thou shalt grant it me for the full price: that the plague may be stayed from the people. 23And Ornan said unto David, Take it to thee, and let my lord the king do that which is good in his eyes: lo, I give thee the oxen also for burnt offerings, and the threshing instruments for wood, and the wheat for the meat offering; I give it all. 24And king David said to Ornan, Nay; but I will verily buy it for the full price: for I will not take that which is thine for the Lord, nor offer burnt offerings without cost. 25So David gave to Ornan for the place six hundred shekels of gold by weight. 26And David built there an altar unto the Lord, and offered burnt offerings and peace offerings, and called upon the Lord; and he answered him from heaven by fire upon the altar of burnt offering. 27And the Lord commanded the angel; and he put up his sword again into the sheath thereof. 28At that time when David saw that the Lord had answered him in the threshingfloor of Ornan the Jebusite, then he sacrificed there. (1 Chronicles 21:15‑28); Isa. 28:27-28; 41:15-1627For the fitches are not threshed with a threshing instrument, neither is a cart wheel turned about upon the cummin; but the fitches are beaten out with a staff, and the cummin with a rod. 28Bread corn is bruised; because he will not ever be threshing it, nor break it with the wheel of his cart, nor bruise it with his horsemen. (Isaiah 28:27‑28)
15Behold, I will make thee a new sharp threshing instrument having teeth: thou shalt thresh the mountains, and beat them small, and shalt make the hills as chaff. 16Thou shalt fan them, and the wind shall carry them away, and the whirlwind shall scatter them: and thou shalt rejoice in the Lord, and shalt glory in the Holy One of Israel. (Isaiah 41:15‑16)). The flail or stick is mentioned (Ruth 2:1717So she gleaned in the field until even, and beat out that she had gleaned: and it was about an ephah of barley. (Ruth 2:17)).
 

Concise Bible Dictionary:

 
 
This is accomplished in the East by the grain being trodden on by oxen, and that it was so threshed in ancient times is shown by the law that the ox should not be muzzled that trod out the corn (Deut. 25:44Thou shalt not muzzle the ox when he treadeth out the corn. (Deuteronomy 25:4)). There were also threshing “instruments,” with which the grain was beaten out. Threshing was also accomplished by oxen drawing over the grain a sort of sledge without runners, by which the straw also was crushed (2 Sam. 24:2222And Araunah said unto David, Let my lord the king take and offer up what seemeth good unto him: behold, here be oxen for burnt sacrifice, and threshing instruments and other instruments of the oxen for wood. (2 Samuel 24:22); Isa. 41:1515Behold, I will make thee a new sharp threshing instrument having teeth: thou shalt thresh the mountains, and beat them small, and shalt make the hills as chaff. (Isaiah 41:15)).
 

Strong’s Dictionary of Hebrew Words:

Number:
1637 (find all occurrences in KJV Bible)
Transliteration:
goren
Phonic:
go’-ren
Meaning:
from an unused root meaning to smooth; a threshing- floor (as made even); by analogy, any open area
KJV Usage:
(barn, corn, threshing- )floor, (threshing-, void) place

From Manners and Customs of the Bible:

The “threshing-floor” was not a shed, or a building, or any place covered with roof and surrounded by walls, but a circular piece of ground from fifty to a hundred feet in diameter, in the open air, on elevated ground, and made smooth, hardy, and clean. Here the grain was threshed and winnowed.