worda character vector specifying the 44 nouns in CWB/Penn format (see convert.lemma)
classa factor vector specifying the semantic class of each noun (bird, fruitTree, green, groundAnimal, tool, vehicle)
class2a factor vector specifying a coarser 3-class categorization (animal, vegetable, artifact)
class3a factor vector specifying a coarser 2-class categorization (natural, artifact)
freq.bnca numeric vector specifying the frequency of each noun in the British National Corpus