WordNet: An On-line Lexical Database

Introduction to WordNet

1. What is WordNet?
   An on-line lexical reference system whose design is inspired by psycholinguistic theories of human lexical memory: English nouns, verbs, adjectives and adverbs are organized into synonym sets (synsets), each representing one lexicalized concept, linked by semantic and lexical relations.
   • Miller et al., 1990, Five Papers on WordNet (Cognitive Science Laboratory, Princeton University (revised 1993; first published in International Journal of Lexicography 3(4), 1990)), Introduction to WordNet
2. What is psycholexicology, and how did it motivate WordNet?
   Miller and Johnson-Laird’s name for psycholinguistic research on the lexicon. Standard dictionaries like the OED focus on historical (diachronic) evidence and neglect the synchronic organization of lexical knowledge; WordNet instantiates psycholinguistic hypotheses about it, and exposes them to the full common vocabulary.
   • Miller et al., 1990, Five Papers on WordNet (Cognitive Science Laboratory, Princeton University (revised 1993; first published in International Journal of Lexicography 3(4), 1990)), Introduction to WordNet
3. Why is WordNet more than “a dictionary as a rapid page-turner”?
   Putting alphabetical dictionaries on line uses computers merely to look things up faster. WordNet organizes the lexicon by meaning rather than form, with the bookkeeping (like two-way look-ups in a thesaurus) done by the computer.
   • Miller et al., 1990, Five Papers on WordNet (Cognitive Science Laboratory, Princeton University (revised 1993; first published in International Journal of Lexicography 3(4), 1990)), Introduction to WordNet
4. Which parts of speech does WordNet contain, and why are function words left out?
   Nouns, verbs, adjectives and adverbs. Function words are assumed to be stored separately as part of the syntactic component of language, supported by observations of aphasic speech.
   • Miller et al., 1990, Five Papers on WordNet (Cognitive Science Laboratory, Princeton University (revised 1993; first published in International Journal of Lexicography 3(4), 1990)), Introduction to WordNet
5. What evidence suggests that syntactic categories are organized differently in memory?
   Word association studies (Fillenbaum and Jones 1965): probes tended to elicit responses of the same category (nouns most strongly, then adjectives, then verbs), which can’t be association by contiguity since adjacent words in text rarely share a category.
   • Miller et al., 1990, Five Papers on WordNet (Cognitive Science Laboratory, Princeton University (revised 1993; first published in International Journal of Lexicography 3(4), 1990)), Introduction to WordNet
6. How is each syntactic category organized in WordNet?
   single organizing principle for all categories would misrepresent the psychological complexity of lexical knowledge.
   • Miller et al., 1990, Five Papers on WordNet (Cognitive Science Laboratory, Princeton University (revised 1993; first published in International Journal of Lexicography 3(4), 1990)), Introduction to WordNet
7. What is the lexical matrix?
   A table with word forms as columns and word meanings as rows; an entry means the form can express that meaning (in context). Two entries in one column: the form is polysemous. Two entries in one row: the forms are synonyms.

   	F1 board	F2 plank	F3 committee
   M1 piece of lumber	✓	✓
   M2 group of people	✓		✓

   • Miller et al., 1990, Five Papers on WordNet (Cognitive Science Laboratory, Princeton University (revised 1993; first published in International Journal of Lexicography 3(4), 1990)), Introduction to WordNet
8. How are polysemy and synonymy complementary?
   Both arise from the many-to-many mapping between forms and meanings: a listener recognizing a form must cope with its polysemy; a speaker expressing a meaning must choose between synonyms.
   • Miller et al., 1990, Five Papers on WordNet (Cognitive Science Laboratory, Princeton University (revised 1993; first published in International Journal of Lexicography 3(4), 1990)), Introduction to WordNet
9. Distinguish constructive and differential theories of lexical meaning. Which does WordNet use?
   A constructive theory represents enough to construct the concept from scratch (standard dictionary definitions often fail this). A differential theory needs only symbols that distinguish meanings. WordNet is differential: a synset like {board, plank} or {board, committee} identifies a concept for someone who already knows it.
   • Miller et al., 1990, Five Papers on WordNet (Cognitive Science Laboratory, Princeton University (revised 1993; first published in International Journal of Lexicography 3(4), 1990)), Introduction to WordNet
10. What is a gloss in WordNet, and when is it used?
    A short definition used when no suitable synonym exists, e.g. {board, (a person’s meals, provided regularly for money)}. Like a synset it only needs to let an English speaker tell this sense from others, not teach the concept.
    • Miller et al., 1990, Five Papers on WordNet (Cognitive Science Laboratory, Princeton University (revised 1993; first published in International Journal of Lexicography 3(4), 1990)), Introduction to WordNet
11. How is synonymy defined for WordNet?
    Relative to context: two expressions are synonymous in a context C if substituting one for the other there doesn’t change truth value (Leibniz’s context-free version makes true synonyms almost nonexistent). Plank for board rarely changes truth in carpentry contexts. In practice it is graded semantic similarity.
    • Miller et al., 1990, Five Papers on WordNet (Cognitive Science Laboratory, Princeton University (revised 1993; first published in International Journal of Lexicography 3(4), 1990)), Introduction to WordNet
12. Why does substitutability force WordNet to partition words by part of speech?
    If synonyms must be interchangeable, words of different syntactic categories can’t be synonyms (can’t share a synset), consistent with evidence that nouns, verbs and modifiers are organized independently in memory.
    • Miller et al., 1990, Five Papers on WordNet (Cognitive Science Laboratory, Princeton University (revised 1993; first published in International Journal of Lexicography 3(4), 1990)), Introduction to WordNet
13. Why is antonymy a lexical relation between word forms rather than a semantic relation between meanings?
    {rise, ascend} and {fall, descend} are conceptual opposites, but the antonym pairs are rise/fall and ascend/descend; people hesitate over rise/descend or ascend/fall. Antonymy also isn’t simply “not-x”: not rich doesn’t imply poor.
    • Miller et al., 1990, Five Papers on WordNet (Cognitive Science Laboratory, Princeton University (revised 1993; first published in International Journal of Lexicography 3(4), 1990)), Introduction to WordNet
14. Define hyponymy and its properties.
    A semantic relation between meanings: {x} is a hyponym of {y} if speakers accept “An x is a (kind of) y” (maple → tree → plant). It is transitive and asymmetric, and with usually one superordinate it forms a hierarchy (an inheritance system); it is the central organizing principle for nouns.
    • Miller et al., 1990, Five Papers on WordNet (Cognitive Science Laboratory, Princeton University (revised 1993; first published in International Journal of Lexicography 3(4), 1990)), Introduction to WordNet
15. Define meronymy.
    The part–whole (HAS-A) relation between meanings: {x} is a meronym of {y} if speakers accept “A y has an x (as a part)” or “An x is a part of y”. It is asymmetric and (with qualifications) transitive; a meronym can have many holonyms.
    • Miller et al., 1990, Five Papers on WordNet (Cognitive Science Laboratory, Princeton University (revised 1993; first published in International Journal of Lexicography 3(4), 1990)), Introduction to WordNet
16. Why did WordNet have to handle inflectional morphology after all?
    A user clicking on trees shouldn’t be told it isn’t in the database, so the interface strips inflections (plural, verb forms) and looks up the base form; derivational morphology was left for the future.
    • Miller et al., 1990, Five Papers on WordNet (Cognitive Science Laboratory, Princeton University (revised 1993; first published in International Journal of Lexicography 3(4), 1990)), Introduction to WordNet