The standard reference work for (semantic) lexical relations is [Cruse 1986]. Other kinds of lexical relation are conventionally dealt with in grammar (collocations, categories, subcategorisation), morphology (such as membership of paradigm classes), and phonology (such as phonetic and distributional similarity of sound structure); the reader is referred to the specialised literature in these areas discussed in the other papers in the present volume. Using terminology from linguistics and language-oriented artificial intelligence, these properties and relations can be characterised in terms of ISA relations and PARTOF relations.