genus rhizoctinia: form genus of imperfect fungi some species of which are now placed in genera Pellicularia and Corticium because their perfect stages have been found
abstraction: a general concept formed by extracting common features from specific examples
lexeme: a minimal unit (as a word or stem) in the lexicon of a language; `go' and `went' and `gone' and `going' are all members of the English lexeme `go'