ergative vs ergative case

ergative

noun
  • An ergative verb or other expression. 

adj
  • With the subject of a transitive construction having grammatical cases or thematic relations different from that of an intransitive construction. 

ergative case

noun
  • A grammatical case used to indicate the agent of a transitive verb in ergative-absolutive languages. 

How often have the words ergative and ergative case occurred in a corpus of books? (source: Google Ngram Viewer )