(ax) head, iron

Boyd’s Bible Dictionary:

(pious). (1) City of Naphtali (Josh. 19:3838And Iron, and Migdal-el, Horem, and Beth-anath, and Beth-shemesh; nineteen cities with their villages. (Joshua 19:38)). (2) Iron, the metal, and copper early known (Gen. 4:2222And Zillah, she also bare Tubal-cain, an instructor of every artificer in brass and iron: and the sister of Tubal-cain was Naamah. (Genesis 4:22)). Prepared in furnaces (1 Kings 8:5151For they be thy people, and thine inheritance, which thou broughtest forth out of Egypt, from the midst of the furnace of iron: (1 Kings 8:51)); used for tools (Deut. 27:55And there shalt thou build an altar unto the Lord thy God, an altar of stones: thou shalt not lift up any iron tool upon them. (Deuteronomy 27:5)); weapons (1 Sam. 17:77And the staff of his spear was like a weaver's beam; and his spear's head weighed six hundred shekels of iron: and one bearing a shield went before him. (1 Samuel 17:7)); implements (2 Sam. 12:3131And he brought forth the people that were therein, and put them under saws, and under harrows of iron, and under axes of iron, and made them pass through the brickkiln: and thus did he unto all the cities of the children of Ammon. So David and all the people returned unto Jerusalem. (2 Samuel 12:31)); war-chariots (Josh. 17:1616And the children of Joseph said, The hill is not enough for us: and all the Canaanites that dwell in the land of the valley have chariots of iron, both they who are of Beth-shean and her towns, and they who are of the valley of Jezreel. (Joshua 17:16)).

“Iron” From Concise Bible Dictionary:

Iron Ore
This metal is mentioned as early as Genesis 4:2222And Zillah, she also bare Tubal-cain, an instructor of every artificer in brass and iron: and the sister of Tubal-cain was Naamah. (Genesis 4:22), when it was used by artificers; and Job speaks of it as dug out of the earth (Job 28:22Iron is taken out of the earth, and brass is molten out of the stone. (Job 28:2)). It was in use in Palestine before the Israelites entered, for they found that the Canaanites had chariots of iron (Josh. 17:16,1816And the children of Joseph said, The hill is not enough for us: and all the Canaanites that dwell in the land of the valley have chariots of iron, both they who are of Beth-shean and her towns, and they who are of the valley of Jezreel. (Joshua 17:16)
18But the mountain shall be thine; for it is a wood, and thou shalt cut it down: and the outgoings of it shall be thine: for thou shalt drive out the Canaanites, though they have iron chariots, and though they be strong. (Joshua 17:18)
). Og king of Bashan had a bedstead of iron, and iron was used for spear heads, threshing instruments, and other such purposes. Iron is used as a symbol of hardness. Israel is described as obstinate; their neck was like an iron sinew and their brow as brass (Isa. 48:44Because I knew that thou art obstinate, and thy neck is an iron sinew, and thy brow brass; (Isaiah 48:4)). The Lord Jesus will rule the nations with a rod of iron (Rev. 12:55And she brought forth a man child, who was to rule all nations with a rod of iron: and her child was caught up unto God, and to his throne. (Revelation 12:5); Rev. 19:1515And out of his mouth goeth a sharp sword, that with it he should smite the nations: and he shall rule them with a rod of iron: and he treadeth the winepress of the fierceness and wrath of Almighty God. (Revelation 19:15)). Iron also characterized the kingdom of Rome. When represented as a beast, it had great iron teeth (Dan. 7:7,197After this I saw in the night visions, and behold a fourth beast, dreadful and terrible, and strong exceedingly; and it had great iron teeth: it devoured and brake in pieces, and stamped the residue with the feet of it: and it was diverse from all the beasts that were before it; and it had ten horns. (Daniel 7:7)
19Then I would know the truth of the fourth beast, which was diverse from all the others, exceeding dreadful, whose teeth were of iron, and his nails of brass; which devoured, brake in pieces, and stamped the residue with his feet; (Daniel 7:19)
); and in the great image the character of the various kingdoms had depreciated from gold to silver, then to brass, thence to iron and clay, that would not unite, the traces of which are seen around us in the national governments of the present day (Dan. 2:33-4533His legs of iron, his feet part of iron and part of clay. 34Thou sawest till that a stone was cut out without hands, which smote the image upon his feet that were of iron and clay, and brake them to pieces. 35Then was the iron, the clay, the brass, the silver, and the gold, broken to pieces together, and became like the chaff of the summer threshingfloors; and the wind carried them away, that no place was found for them: and the stone that smote the image became a great mountain, and filled the whole earth. 36This is the dream; and we will tell the interpretation thereof before the king. 37Thou, O king, art a king of kings: for the God of heaven hath given thee a kingdom, power, and strength, and glory. 38And wheresoever the children of men dwell, the beasts of the field and the fowls of the heaven hath he given into thine hand, and hath made thee ruler over them all. Thou art this head of gold. 39And after thee shall arise another kingdom inferior to thee, and another third kingdom of brass, which shall bear rule over all the earth. 40And the fourth kingdom shall be strong as iron: forasmuch as iron breaketh in pieces and subdueth all things: and as iron that breaketh all these, shall it break in pieces and bruise. 41And whereas thou sawest the feet and toes, part of potters' clay, and part of iron, the kingdom shall be divided; but there shall be in it of the strength of the iron, forasmuch as thou sawest the iron mixed with miry clay. 42And as the toes of the feet were part of iron, and part of clay, so the kingdom shall be partly strong, and partly broken. 43And whereas thou sawest iron mixed with miry clay, they shall mingle themselves with the seed of men: but they shall not cleave one to another, even as iron is not mixed with clay. 44And in the days of these kings shall the God of heaven set up a kingdom, which shall never be destroyed: and the kingdom shall not be left to other people, but it shall break in pieces and consume all these kingdoms, and it shall stand for ever. 45Forasmuch as thou sawest that the stone was cut out of the mountain without hands, and that it brake in pieces the iron, the brass, the clay, the silver, and the gold; the great God hath made known to the king what shall come to pass hereafter: and the dream is certain, and the interpretation thereof sure. (Daniel 2:33‑45)).

“Iron That Swims” From Concise Bible Dictionary:

He cuts down that stick and casts it in the very place where I lost my "ax head." I am the only one who can tell Him. It is my own experience. But do I have anything to do with what takes place next? No, not a bit. A miracle happens. The iron comes to the surface. Yet the story doesn't say that. It says, "The iron did swim."
Why does it say iron instead of ax head? Because iron has a nature that doesn't swim. But the iron did swim-it is the law of the principle of the spirit of life in Christ Jesus. It has set me free from the principle of sin and death. It is an entirely new law not known before. Could man explain how a piece of iron could swim? Never! It doesn't belong to the old line of things at all; it is a new thing.
I still have the same identity I had as a man before, but the old nature is gone. My identity with sin in the flesh is gone. I may allow it to come out again, but that is why Romans says, "Reckon ye also yourselves to be dead indeed unto sin." Practically, by faith, take the place you are in; that is what Romans tells us, because the man is still struggling. In Colossians he says, "Ye are dead." Then he sets a positive fact before them-life.
In Rom. 7 the man is still struggling; he is still trying to build himself a place by Jordan where he may rest, where he may dwell, and so the exhortation in Romans is, "Reckon... yourselves... dead." Do I need that exhortation for my soul? Do you need it for your soul? Are we still struggling or are our souls at rest? Are we resting in the full work of Christ? We are not to be occupied with our former manner of life in the flesh. In Christ is where I find joy. We need to be exercised about these things, each one, before the Lord.

Strong’s Dictionary of Hebrew Words:

perhaps from the root of 1269; iron (as cutting); by extension, an iron implement
KJV Usage:
(ax) head, iron