Noun Postmodification: Appositive Noun Phrases

Postmodification with Appositive Noun Phrases

Nouns are sometimes post-modified with other noun phrases. In academic writing these noun phrases are used provide to extra information, clarification, examples, formulae, and acronyms. They may be enclosed by commas but are often enclosed in parentheses, as in the examples below.

Appositive noun phrases are useful in printed text but with digital media there are other ways of supplying extra information.

Clarification

A noun phrase in apposition is often used to give a definition or explanation of a word or phrase which the writer expects the reader might not know.

• chitin the material that makes up the bulk of the exoskeleton of insects)      (context)

  This quite long appositive noun phrase simply explains what chitin is.

• a planetary nebula (essentially a cloud around the star),      (context)

  This gives a brief (note the word "essentially") definition of a planetary nebula.

• cognitive flexibility' (our ability to shift perspective easily)      (context)

  This gives a brief definition of “cognitive flexibility”.

Acronyms

Acronyms are abbreviations of noun phrases which are likely to be repeated in a text or which have become part of common usage (e.g. DNA).

• compact fluorescent lamp (CFL)      (context)
• seasonal affective disorder (SAD)      (context)
• James Webb space telescope (JWST)appositive noun phrase in the form of an acronym      (context)

Formulae

Like acronyms, formulae are just shortened forms of longer phrases. Some of these, like mathematical formulae, would be quite complex to write out in full. The reason we use them is to pack a lot of information into a short space, which allows us treat a complex idea as a simple unit.

• the formula 4πr²      (context)
• methane (CH₄), nitrous oxide (N₂O)      (context)

Extra Information

Sometimes appositive noun phrases are used to provide some extra information, useful or interesting but not strictly necessary, like dates, conversions to other units, Latin names, people's professions, etc.

• Eratosthenes (276BC to 195 BC)      (context)
• 3,959 miles (6,371 kilometers)      (context)
• bitter vetch (Vicia ervilia), grass pea (Lathyrus spp) and wild pea (Pisum spp)      (context)
• the 18th-century English scholar (Thomas Bayes)      (context)
• the same “big three” glaciers (Jakobshavn Isbrae in the west of the island and Helheim and Kangerlussuaq in the east)      (context)

Examples

Examples of something mentioned, or lists of items in a category, are often placed in appositive noun phrases.

• molluscs (snails, for example) or annelids (earthworms)      (context)
• the five planets then known (Mercury, Venus, Mars, Jupiter, and Saturn)      (context)