What is a compound

What Is Compounding in the English Language?

In English grammar, compounding is the process of combining two words (free morphemes) to create a new word (commonly a noun, verb, or adjective). Also called composition, it is from the Latin for «put together».

Compounds are written sometimes as one word (sunglasses), sometimes as two hyphenated words (life-threatening), and sometimes as two separate words (football stadium). Compounding is the most common type of word-formation in English.

Types of Compounds

Compounding exists in several different forms and parts of speech, including the following:

Examples and Observations

Stress Test

«Typically a compound begins as a kind of cliché, two words that are frequently found together, as are air cargo or light colored. If the association persists, the two words often turn into a compound, sometimes with a meaning that is simply the sum of the parts (light switch), sometimes with some sort of figurative new sense (moonshine). The semantic relationships of the parts can be of all kinds: a window cleaner cleans windows, but a vacuum cleaner does not clean vacuums. We can be sure we have a compound when the primary stress moves forward; normally a modifier will be less heavily stressed than the word it modifies, but in compounds, the first element is always more heavily stressed.» (Kenneth G. Wilson, «The Columbia Guide to Standard American English». Columbia University Press, 1993)

Distinguishing Features of Compounds

«[In most compounds] the rightmost morpheme determines the category of the entire word. Thus, greenhouse is a noun because its rightmost component is a noun, spoonfeed is a verb because feed also belongs to this category, and nationwide is an adjective just as wide is.

«English orthography is not consistent in representing compounds, which are sometimes written as single words, sometimes with an intervening hyphen, and sometimes as separate words. In terms of pronunciation, however, there is an important generalization to be made. In particular, adjective-noun compounds are characterized by a more prominent stress on their first component.

«A second distinguishing feature of compounds in English is that tense and plural markers cannot typically be attached to the first element, although they can be added to the compound as a whole. (There are some exceptions, however, such as passers-by and parks supervisor.)» (William O’Grady, J. Archibald, M. Aronoff, and J. Rees-Miller, «Contemporary Linguistics: An Introduction». Bedford/St. Martin’s, 2001)

Plurals of Compounds

«The following two compounds are exceptional in taking the inflection on the first element:

«A few compounds ending in -ful usually take the plural inflection on the last element, but have a less common plural with the inflection on the first element:

«Compounds ending in -in-law allow the plural either on the first element or (informally) on the last element:

(Sidney Greenbaum, «Oxford English Grammar». Oxford University Press, 1996)

Compounds in the Dictionary

«Evidently, the definition of what counts as a single dictionary entry is fluid and allows for very wide margins; any attempt at further precision is impossible because of the unlimited potential for compounding and derivation. The OED [Oxford English Dictionary] policy on compounds and derivatives is indicative of how blurred the line between a ‘headword’ and a compound or a derivative can be:

Clearly, the size of the dictionary records exceeds by far the vocabulary of an individual speaker.» (Donka Minkova and Robert Stockwell, «English Words.» «The Handbook of English Linguistics», ed. by Bas Aarts and April McMahon. Blackwell, 2006)

Compounding in Shakespeare’s King Lear

«Amid the forceful modifiers of ‘oak-cleaving’ and ‘all-shaking’ are the ‘thought-executing’ ‘vaunt-couriers’: lightning bolts.» (John Kelly, «Forget His Coinages, Shakespeare’s Real Genius Lies in His Noggin-Busting Compounds.» Slate, May 16, 2016)

Matter can be classified in various ways according to its structure, behaviours and physical and chemical properties.

Definitions of a Chemical Compound:

A compound is a pure substance that consists of two or more elements chemically combined in a fixed proportion, that can be further subdivided into simpler substances by chemical (not physical) means only. . So, if a quantity of a material consists of atoms of two or more elements joined together, always in the same ratio, then the matter forming that material is a compound.

List of facts about Compounds:

A compound can be represented by a chemical formula.

A molecule is the smallest part of a compound whose properties are those of the compound.

Compounds consist of molecules, which are formed from atoms.

In the following diagram:

Atoms are represented by single spheres.
Spheres of the same size and colour represent atoms of the same element.

Molecules are represented by two or more spheres joined together.

Molecules of Elements would be represented by two or more spheres of the same size and colour joined together.

Molecules of Compounds are represented by two or more spheres of different sizes and colours joined together, as shown below.

Note : This is one of a series of simple pages introducing key concepts in introductory chemistry. Other pages in this section include elements, mixtures and compounds and individual pages about substances, elements, mixtures and compounds, plus pages about atoms, molecules and isotopes. If you need further information ask your chemistry tutor.

Anybody Can Learn About Compound Words. Here’s Everything You Need To Know

Compounds words are when two or more words are joined together, creating a new word. Read on to learn about the many types of compound words.

Some compounds have more than two words, like “mother-in-law.”

Correct Use

What Are Compound Words?

What do a honeybee, butterfly, earthworm, and jitterbug have in common? That they’re all insects? Nope! That they’re compound words. We’ll teach you everything you need to know about compound words, from what they are to the different types.

Think of the word fire. You might be picturing something similar to flames of bright light, heat, and smoke. Now, think of the word fighter. You’re most likely thinking of something or someone that fights, like a boxer or soldier. Now, put these two words together: firefighter. What do you imagine? A person whose career is to put out and extinguish fires. This is an example of a compound word—two words with separate meanings combined to create an entirely new word.

“Firefighters” (closed compound) use “firetrucks” in their line of work. The latter is an example of a compound word that is sometimes written opened, and sometimes closed.

Types of Compound Words

There are a few types of compound words, including:

These can be written as either open, closed, or hyphenated compounds. Open compounds are compounds that have a space between each word (e.g., full moon). Closed compounds don’t have a space (e.g., daybed), and hyphenated compounds have a hyphen separating each word (e.g., up-to-date).

Compound Nouns

A compound noun is made up of a noun plus another noun. Take moonlight as an example. However, compound nouns are also made using other parts of speech, like verbs and adjectives.

Think of the word haircut. Hair on its own is a noun. Cut is often used as a verb, but when you put those two words together, it becomes a noun again. Please note that the order of a compound noun is not limited to noun + noun, or noun + other parts of speech. Many combinations can produce a compound noun. For example, a verb + a noun can also create a compound noun (e.g., swimsuit).

“Fireworks” is another example of a “noun + verb compound noun.”

There are opened, closed, and hyphenated compound nouns. Below are a few examples of each.

Often, many words start as open compound words, and eventually turn into closed compound words (e.g., notebook). There are a few standards that can be remembered to know whether a compound word should be opened, closed, or hyphenated. For example, a noun + noun compound word is usually closed (e.g., boyfriend). A compound word that uses a verb + “ing” is often written as an open compound (e.g., dry cleaning).

Compound Adjectives

Compound adjectives are two words joined into one to describe a noun (or compound noun). Like compound nouns, they can contain different parts of speech. Compound adjectives are mostly written with hyphens, but there are also opened and closed forms of these words.

Here are a few examples of compound adjectives:

Last time she walked by the lake, she saw a seven-foot-long alligator.

They were in a long-distance relationship for seven years.

A new school had to be built because the old one was overpopulated.

Quick Tip

As with most English language rules, the rules for compound nouns and compound adjectives are not set in stone. Knowing when to use what type of compound word takes practice and familiarization. Your best bet would be writing with an easy-to-use spell and grammar checker like LanguageTool. Not only will this writing assistant make sure you consistently use the correct form of a compound word, but it will also conveniently provide synonyms and offer stylistic improvements.

Compound Verbs

There are several types of compound verbs, like phrasal verbs, prepositional verbs, and helping verbs. Here, we are only going to focus on single-word compound verbs. Like in compound nouns and adjectives, these verbs are made by joining two words. Below are a few examples of compound verbs:

I was looking for someone who could babysit my kids for the weekend.

For her birthday, she wanted to test-drive a new Ferrari.

He had to sound-proof his apartment.

Keep in mind that compound verbs are usually written with a hyphen or as a closed compound.

When it comes to compound words, here’s what you should remember: There are many types, like compound nouns, adjectives, and verbs. These can come as open compound words (which have a space between the words), closed compound words (don’t have a space), and hyphenated compounds (the words are separated by a hyphen).

Many compound words have multiple acceptable ways of being written. Sometimes, they start with a space and through years of use, the space is eventually removed. The ambiguity of compound words is what makes them difficult to master. That’s why it’s worth reiterating that you should always have a user-friendly text editor like LanguageTool to help you get the correct spelling (and spacing) of compound words.

compound

A compound differs from a mixture, in which bonding among the atoms of the constituent substances does not occur. In some situations, different elements react with each other when they are mixed, forming bonds among the atoms and thereby producing molecules of a compound. In other scenarios, different elements can be mixed and no reaction occurs, so the elements retain their individual identities. Sometimes, when elements are mixed, the reaction occurs slowly (as when iron is exposed to oxygen); in other cases it takes place rapidly (as when lithium is exposed to oxygen). Sometimes, when an element is exposed to a compound, a reaction occurs in which new compounds are formed (as when pure elemental sodium is immersed in liquid water).

Often, a compound looks and behaves nothing like any of the elements that comprise it. Consider, for example, hydrogen (H) and oxygen (O). Both of these elements are gases at room temperature and normal atmospheric pressure. But when they combine into the familiar compound known as water, each molecule of which contains two hydrogen atoms and one oxygen atom (H ₂ O), the resulting substance is a liquid at room temperature and normal atmospheric pressure.

The atoms of a few elements do not readily bond with other elements to form compounds. These are called noble or inert gases: helium, neon, argon, krypton, xenon, and radon. Certain elements readily combine with other elements to form compounds. Examples are oxygen, chlorine, and fluorine.

What Is a Compound in Chemistry? Definition and Examples

In chemistry, a compound is a substance made of two or more elements chemically bonded to each other in a fixed ratio. The chemical bonds between atoms of elements involve a transfer or sharing of valence of electrons. This give a compound different properties from its elements. A compound may be represented by a chemical formula that shows the element symbols of the atoms and their proportions.

Examples of Compounds

Examples of compounds include any substance with more than one element and a fixed ratio between them. For example, the ratio between hydrogen and oxygen atoms in a water molecule (H₂O) is always 2:1. Whether you have a milliliter or 50 liters of water, every particle has the same 2:1 ratio between hydrogen and oxygen atoms. This ratio is important because the same elements can combine in different proportions to form compounds with completely different properties. For example, water (H₂O) is quite different from hydrogen peroxide (H₂O₂), even though they both consist of hydrogen and oxygen atoms.

Examples of compounds and their names include:

Examples of substances which are not compounds include the hydrogen ion (H + ) and the noble gas elements (e.g., Ar, Kr, Ne). Because there is only one element, the pure metals and diatomic nonmetals often are not considered to be compounds (e.g., gold, copper, H₂, F₂).

Difference Between a Compound and a Molecule

All compounds are examples of molecules, but not all molecules are compounds.

According to the International Union of Pure and Applied Chemistry (IUPAC), a molecule is defined as an electrically neutral substance consisting of more than one atom. This includes compounds, plus it includes diatomic and triatomic elements, such as oxygen (O₂), chlorine (Cl₂), and ozone (O₃). By this definition, many superconductors are molecules, but not compounds, because their chemical formula does not have a fixed ratio. An example is a YBCO superconductor, which has a formula YBa₂Cu₃O_7-x. (x could be 0.15).

Types of Compounds

Compounds are classified according to the type of chemical bonds formed between the atoms. These bonds may be ionic, covalent, metallic, or a mixture of ionic and covalent bonds.

How to Write Compound Formulas

Compound names and formulas are written listing the atom or group of atoms acting as a cation first, followed the atom or group of atoms acting as an anion second. Because atoms of elements have different oxidation states, an element may be in either the beginning or end of the formula, depending on other elements. For example, carbon (C) is a cation in carbon dioxide (CO₂) and anion in silicon carbon (SiC).

The number of atoms of an element are indicated using subscripts. If there is only one atom of an element, the subscript is omitted. Water is a compound made of two hydrogen atoms (H) and one oxygen atom (O). H₂O is correct, but H₂O₁ is not. Table salt (sodium chloride) consists of one sodium atom bonded to one chlorine atom. Its chemical formula is NaCl and not Na₁Cl₁.