Content word

In linguistics, content words are words that possess semantic content and contribute to the meaning of the sentence in which they occur. In a traditional approach, nouns were said to name objects and other entities, lexical verbs to indicate actions, adjectives to refer to attributes of entities and adverbs, to attributes of actions. They contrast with function words, which are words that have very little substantive meaning and primarily denote grammatical relationships between content words, such as prepositions (in, out, under, etc.), pronouns (I, you, he, who, etc.), conjunctions (and, but, till, as, etc.), etc.[1]

All words can be classified as either content or function words, although it is not always easy to make the distinction. With only around 150 function words, 99.9% of words in the English language are content words. Although small in numbers, function words are used at a disproportionately higher rate and make up about 50% of any English text. This is due to the conventional patterns of words usage which bind function words to content words almost every time they are used, creating an interdependence between the two word groups.[1]

Content words are usually open class words, meaning new ones are easily added to the language.[2] In relation to English phonology, content words generally adhere to the minimal word constraint of being no shorter than two morae long (i.e., a minimum length of two light syllables or one heavy syllable), while function words often do not.[3]