The concept of wordhood is unclear despite being intuitive and central to linguistics.

There has been some theoretical work on the nature of entities like phrases and words in linguistics. For example, Ross (2010) argues that the concept of parts of speech is fuzzy. Similarly, Szabó (2015) rejects the idea that parts of speech should be identified by distributional analysis as is common in syntax. Instead he offers a semantic approach based on predicate logic where the aim is to model the major lexical categories directly in terms of open class constants. This, he claims, results