Word structure: Compounds

Compounds are combinations of root words, i.e. words that can occur on their own, to form a new established combination. They are sometimes spelt as one word, but also with a hyphen or as two words.

In English compound nouns, e.g. bookcaselaptopsmartphone, and compound adjectives, e.g. dripping wettax-free, are very common.

Look at the following words. Can you see some patterns of relationship among them? Can each word be broken down into meaningful parts?

  • biology, biography, geology, geography, psychology, psychopathy, sociology, sociopathy

You may have noticed the following elements appearing several times:

  • bio-, geo-, psycho-, socio-
  • -logy, -graphy, -pathy

These are called combining forms. They are meaningful elements drawn from Greek and Latin, which can combine with other elements to form words. Words that contain a common combining form like this are members of the same word family.

Words formed in this way are called neoclassical compounds. This term is used because the word elements were taken from the classical languages (ancient Greek and Latin) and were combined in new ways in English (the element neo- comes from the Greek for ‘new’). Neoclassical compounds are an important part of the more scholarly vocabulary of English, including scientific terminology.

Many of the combining forms, like socio-, are unable to stand alone as words and are found only as parts of larger words. Although we are calling these larger words (like sociology) compounds, they are different from the more typical type of compound (like girlfriend) where each part can stand alone as a separate word.

However, some of the combining forms do occur as separate words. For example, phobia occurs in words like technophobia, homophobia and xenophobia, but is also a word in its own right, with a more general meaning.

Also, some of the combining forms have given rise to informal independent words through the process of clipping (shortening). For example, psycho has been ‘clipped’ from psychopath, and phone from telephone.

As a further complication, some compounds are made up of one combining form and one element which is a normal independent word. For example, sociolinguistics combines socio- and linguistics; biodegradable combines bio- and degradable.

In these ways, the combining forms make important contributions to the richness of English vocabulary. It can be very helpful to know about these forms and their meanings, as you can often use this knowledge to make sense of words you are encountering for the first time.

For example, you might have noticed that -logy or -ology is found in many words for different branches of knowledge or areas of study, like these:

  • biology, geology, technology, sociology, psychology

If you then come across the word volcanology, you can probably make a confident prediction about its meaning, and work out what a volcanologist does.

Or suppose you learn that the combining form neuro- means ‘relating to nerves or the nervous system’ (the nervous system includes the brain, spinal cord and all the nerves in the body). This will help you to understand numerous words, such as these:

  • neurosurgery, neuroscience, neuromuscular, neurology, neurobiology


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