fourth person

Short definition from Wiktionary

Noun

1. 1
   A variety of the third person sometimes used for indefinite referents, such as one, as in one shouldn't do that.
2. 2
   grammatical person in some languages distinct from first, second, and third persons, semantically translated by one of them in English. For example, in Ojibwe, it is a variety of the third person used for a secondary, or obviative, third person.