A Wordnet from the Ground Up

24 Chapter 2. Building a Wordnet CoreThe second style of synonymy definitions is based on mutual hypernymy (Lyons,1989, Section 9.4). If A is a synonym of B, then “A is a kind of B” and “B is a kindof A”. For example (Derwojedowa et al., 2008), ascending is a kind of going up andthe other way around, and so are animal and beast. Though girl is a kind of a woman,however, not all women are girls. Synonymy test can be assisted a substitution testof the kind we present in Appendix A (actually applied in plWordNet). We believethat a definition based on mutual hypernymy allows more subtle and less arbitrarydiscrimination of synonyms (or near-synonyms): the question asked in the test requiresa simple yes-no answer and does not enforce an evaluation of the change.This summary of Sections 1.1.1 and 1.1.2, together with a brief overview of synonymydefinitions, emphasises the main points to which every wordnet designer mustrefer. Usually the structure of a wordnet strictly follows the PWN assumptions. A wordnet,however, tends also to be treated – and used – as a useful language resource that describeslexical semantics. The organisational principles must be clear when it comes tothe fundamental unit of description – the word (with the inevitable language-dependentdifferences of opinion on what constitutes a word). There is justified doubt whetherthe synonymy relation and relations between concepts are a basis precise enough to bethe underpinning of a wordnet.The ontological and psychological status of a concept is not clear, nor is the relationbetween the concept, the word and the world. It is well known that expressions can havethe same referent but different meaning, so they cannot be considered synonymous, asin Frege’s famous pair “the morning star” and “the evening star”.Some word forms can have the same designative meaning but different expressivemeaning. For example, ręka, łapa, graba and grabula all mean ‘hand’. Only ręka isneutral, and can be described as a meronym of ciało ‘body’ and a holonym of dłoń‘palm’, ramię ‘shoulder”, przedramię ‘forearm’. 1 On the other hand, graba ‘mitt’ doesnot have such meronyms or holonyms.Some word forms freely replaceable in many contexts are not synonymous: considerI was bit by a bulldog/dog. In fact, bulldog is a hyponym of dog. The word mak‘poppy’ can be accurately described as denoting a flower, weed or herb, but it doesnot mean that a flower, a weed and a herb are synonyms (Derwojedowa et al., 2008).In PWN, semantic relations (except antonymy and derivational relations) hold betweensynsets – that is to say, between lexicalised concepts – rather than between wordforms (Fellbaum, 1998a, p. 210). The lexicalised concept, however, is characterisedonly as an unspecified, abstract semantic object which represents the part of the meaningof synset members that is common to all of them (Miller et al., 1993). A relationbetween concepts, therefore, is a relation defined in the space of abstract objects; itsassociation with the lexical meaning relations is not direct or obvious. Without a pre-1 In the colloquial usage, ręka refers to the shoulder, arm, forearm and hand together.