Real Dictionary

ergative
adjective: An ergative verb is a verb that can be both transitive and intransitive, where the subject of the intransitive verb is the same as the object of the transitive verb. For example, ' open' is an ergative verb because you can say 'The door opened' or 'She op

ergative in American English
designating, of, or in the case that is taken by the subject of a transitive verb in some languages, as Basque or Georgian, in which the direct object of a transitive verb and the subject of the related intransitive share the same case
adjective: noting a case that indicates the subject of a transitive verb and is distinct from the case indicating the subject of an intransitive verb

ergative in British English
adjective: denoting a type of verb that takes the same noun as either direct object or as subject, with equivalent meaning. Thus, " fuse" is an ergative verb: "He fused the lights" and "The lights fused" have equivalent meaning
noun: an ergative verb