Word Connections: Iron & Coal

In this episode of Word Connections, we look at the words “iron” and “coal”, tracing an intricate web of links to other English and European words. Along the way, we also touch briefly on several scientific details that are connected to these same words.

Iron and coal are both natural materials that are mined from the earth in great quantities. Both are key ingredients in the manufacture of steel. The great steel-making areas of the world are typically located in places where both iron and coal are readily available — either because both materials can be mined nearby, or because both materials can be brought in easily by ship or by rail.

The word “iron” is from the Old English īren. An earlier form of the word in Old English was īsern. Another variation also found in Old English is īsen, which is nearly identical to the modern German word for iron, Eisen. However, due to the Great Vowel Shift, which affected both English and German, the sound of the initial vowel has changed since the days of Old English. (The first syllable of īren was pronounced like the “i” in “ski”.) The word is thought to have originated in an early Celtic language, prior to its entry into the Germanic languages.

The French word for “iron” is fer, while the Italian and Portuguese words are ferro. All of these words are derived from ferrum, the Latin word for iron. English words that are derived from the Latin ferrum include “ferrite” (a ceramic made from iron oxide), “ferromagnetism”, and “ferruginous”. The last term originally meant “containing iron”, as in “ferruginous sandstone”. Iron oxide in this sandstone gives it a rusty color, and therefore the word “ferruginous” developed a second meaning, which is “rust-colored” — as in the ferruginous hawk, which has rust-colored areas on its body.

In English, we use the words “ferrous” and “ferric” — both of which are derived from ferrum — to denote chemical compounds that contain iron. Examples include ferrous sulfate and ferric chloride. The difference between “ferrous” and “ferric” is the valence of the iron atoms. The word “valence” refers to how many electrons an atom shares with the neighboring atoms. Iron is a bit unusual in that it is perfectly happy to share either 2 or 3 electrons. These two states of sharing are called “divalent” and “trivalent” iron. The divalent state used to be called “ferrous”, as in ferrous oxide (FeO), and the trivalent state was called “ferric”, as in ferric oxide (Fe2O3). But now the preferred terminology is to use the word “iron” with a valence number in parentheses. Therefore FeO is now called iron (II) oxide, and Fe2O3 is now called iron (III) oxide. Rust, the familiar reddish material that develops on exposed iron, consists of a mixture of several hydrated forms of iron oxide.

The Spanish word for iron is hierro, also derived from the Latin word ferrum. This word illustrates two common patterns in Spanish words. The first pattern is that the initial “f” in many Latin words has changed to “h” in the corresponding Spanish words. (Compare horno, the Spanish word for oven, with forno, the corresponding word in both Portuguese and Italian.) The second pattern is that Spanish words containing “ie” are usually from Latin words where the vowel was simply “e”. (Compare nieve, the Spanish word for snow, with neve, the corresponding word in both Portuguese and Italian.) Therefore hierro is an interesting example of both patterns occurring in a single word, contrasting with the word ferro in Portuguese and Italian. These Spanish patterns are not completely consistent. For example, the Spanish word ferrocarril, which means “railroad”, is also derived from ferrum and does not exhibit either pattern. The word ferrocarril is a compound word that literally means “iron rail” or “iron lane”. A lane in a highway is also called a carril. The Spanish word carril and the English words “carry”, “carriage”, “cart”, and “car” are all descended from the Latin word carrus, which meant a cart or any other wheeled vehicle.

Spanish is not the only language where the word for “railroad” is a compound word involving “iron”. The German word for railroad is Eisenbahn, which literally meant “iron path”. (Similarly, a highway in German is an Autobahn, a path for automobiles.) However, in modern German the word bahn usually just means “train”. The French term for railroad is chemin de fer, which also literally means “iron path”. Chemin, the French word for “path”, is related to the Spanish word camino, which means a path or route — as in the Camino Real. The Spanish word caminar, meaning “walk”, is from the same origin.

In English, we say “railroad” instead of “iron-path” or “iron-road” — but the rails are made of iron, so we have an indirect reference to the metal. At one time some people called a railroad locomotive an “iron horse”, so we have a direct reference too.

The Spanish word for “tool”, herramienta, is derived from the Latin ferrum, combined with the Latin suffix mentum, which means “instrument”. Therefore herramienta literally means an instrument made of iron. In this word the first “e” did not change to “ie”, but the second “e” did change — rather strange! The Portuguese word for tool is ferramenta, preserving the “f” and both examples of “e” from its Latin origin. By comparison, the Italian word for tool is strumento, from the same Latin origin as the English word “instrument” — and these words do not contain any reference to iron.

On the other hand, in English we have a common household appliance that we call an “iron”. We use this tool to remove wrinkles from clothing. We even use the word “iron” as a verb to describe the process, as in “I’ve got so many shirts to iron this weekend!” Today’s irons are electrical devices with knobs, a cord, a chamber filled with water, and the ability to steam the clothing during the ironing process. But the original irons were nothing more than a solid piece of cast iron, flat on one side and with a handle attached to the other side. There were no electrical components to heat the iron — you would typically heat it on a stove. So it was quite natural to call a simple tool made of solid iron an “iron” — or sometimes a “flatiron”. And therefore the process of using an iron to remove wrinkles from clothing is called “ironing”.

In some other languages, the word for “ironing” was derived in a very different manner. For example, in Spanish the verb that means “to iron” is planchar, from the Latin word planca, which means “board”. The idea, apparently, is that when you do ironing, you do it on a board — and you also make the clothes as flat as a board. The English word “plank”, which means a flat piece of wood, is also from the Latin planca. An ironing board in Spanish is a tabla de planchar, where tabla means table or board. In French the word that means “to iron” is repassar, which literally means “to pass again”. The French term for ironing board is planche à repasser. The word planche means plank or board, and is from the same root as the English word “plank” and the Spanish word planchar. Therefore we have the fascinating situation where the Spanish term for ironing board (tabla de planchar) and the French term for ironing board (planche à repasser) both contain a word descended from the Latin planca — but in Spanish the word refers to the “ironing” part of ironing board, and in French the word refers to the “board” part of ironing board.

At one time the word “iron” could mean any simple tool made of solid iron, or even a rod of iron. Today we still refer to certain types of golf clubs as “irons”. We also have the expression “He has too many irons in the fire”, which is not a reference to ironing clothes, or to playing golf. Instead, this expression refers to a blacksmith shop, where the smith heats his rods of iron in a forge before hammering them into shape. This expression draws an analogy with a blacksmith who heats too many rods of iron in the forge — more than he could possibly hammer. Therefore the expression has a meaning somewhat similar to another expression: “He bit off more than he could chew.”

In English, in addition to the word “iron”, we have the words “irony” and “ironic” that look as if they might be closely related. But in fact “irony” has a completely different origin than “iron” — so the similarity in appearance is just a coincidence.

From a historical and cultural standpoint, the mining of iron is closely associated with the mining of coal, because both materials are needed to make steel. Steel is an alloy of iron and carbon, with iron being the principal component. (Some types of steel, including stainless steel, include additional metals in the mix.) The carbon in steel comes from coal, and constitutes up to 2% of the finished steel. Steel is much stronger than pure iron, and much of that extra strength comes from the interaction between the iron and carbon atoms.

In English, the word “coal” has two meanings — one is a black, combustible rock-like material that is dug up from the ground — actually the compressed remains of plants that lived many millions of years ago. The other meaning is a glowing ember in a fire. In fact, the latter meaning is the original. The word “coal” is from the Old English col, which meant a glowing ember or a charred remnant. The modern German word for coal is Kohle, and the Dutch word is kool. Both of these words — and the Old English word too — are pronounced essentially the same as our modern word “coal”. The Scandinavian words for coal are similar — the Swedish word is kol; the Danish word is kul; and the Norwegian word is kull.

The Spanish word for coal is carbón, which except for the accent mark looks just like the English word “carbon” — a chemical element in the periodic chart. Thus we can speak of an atom of carbon. The principal element in coal is carbon, so the association makes sense. The English word “carbon” and the Spanish word carbón are both derived from the Latin word carbō, which means “charcoal”. Charcoal looks a lot like coal, and it can be burned in a similar manner to coal. And like coal, the predominant element in charcoal is carbon. But unlike coal, charcoal is not mined. Instead, we produce charcoal by heating wood in the absence of oxygen, or by some similar process. Because the molecules in the resulting material have not been combined with oxygen, the material can still be burned — even though the black material looks like something that has already been burned.

Several other languages also use a word similar to carbón to mean coal. For example, the Italian word for coal is carbone, the French word is charbon, and the Greek word is karvono (κάρβουνο). Since these languages use a word similar to “carbon” to mean “coal”, then how do you say “carbon”? The French word for carbon is carbone, spelled the same as the Italian word for coal. The Italian word for carbon is carbonio, and the Spanish word is carbono. In short, all of these words are quite similar to the corresponding words for coal.

In contrast to the above examples, the German word for carbon is Kohlenstoff, which literally means “coal stuff” or “material from coal”. Likewise the Dutch word for carbon is koolstof, and the Danish word is kulstof — both of which are quite similar to the German. (So if a Dane tells you that he has some “cool stuff”, perhaps he just means that he has some carbon.)

In English we have a term “carbonated water”, which refers to that fizzy water from which soft drinks are made. It’s a very common term, but what does it really mean? Well, it doesn’t mean that you stir some carbon into the water. To make carbonated water, you dissolve carbon dioxide (which is quite different from elemental carbon) in water. This may sound odd, because carbon dioxide is a gas, but many types of gas can dissolve in water. In fact, much of the carbon dioxide gas that enters our atmosphere ends up dissolving in the ocean. There is an equilibrium between the carbon dioxide in the atmosphere and the carbon dioxide in the ocean. If you increase the carbon dioxide in either place, then a new equilibrium occurs, and you end up with a net increase in both places.

As it turns out, water can hold a lot more dissolved carbon dioxide if the water is under pressure. So the secret to carbonated water is to subject the water to high pressure in an enclosed space. The little bit of “air space” in the beverage container actually contains pressurized carbon dioxide. If you look at a clear bottle of a carbonated beverage before the top is removed, you won’t see any bubbles. But when the cap is removed, releasing the pressure, then the equilibrium shifts, and the water can no longer hold as much dissolved carbon dioxide. Therefore the carbon dioxide returns to the form of a gas, which gathers into little bubbles which rise to the top of the liquid.

All of this might sound a little bit surprising, but equally surprising is that the dissolved carbon dioxide isn’t really carbon dioxide anymore. Instead, during the time that it is dissolved in the water, each molecule of carbon dioxide (CO2) links up with a molecule of water (H2O) to form a molecule of carbonic acid (H2CO3). So the equilibrium is actually between carbon dioxide in the air and carbonic acid in the water. And believe it or not, this brings us around to how the Germans say “carbonated”. If you look on a bottle of carbonated water in Germany, it will say mit Kohlensäure. The word mit means “with”. The word säure means “acid” — from the same root as the English word “sour”. The word Kohle, as we saw earlier, means coal. Therefore the phrase mit Kohlensäure literally means “with coal acid”. Doesn’t that sound yummy! As you have probably guessed, Kohlensäure is the German word for carbonic acid — which is the form that the dissolved carbon dioxide takes. In short, the German phrase mit Kohlensäure is how to say “carbonated” — a useful phrase if you should find yourself traveling in Germany!

That concludes this episode of Word Connections, featuring the words “iron” and “coal”. Additional episodes will continue to appear in The Philipendium on a regular basis!

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