jener meaning and definition in german

In formal writing, jener is not an uncommon word. It is used when the antecedent stands relatively far away from the pronoun, particularly if another word that could be the antecedent, is closer. Compare:
Der Erfolg der Firma bei der jüngeren Zielgruppe beweist, dass jene sich verändert hat.
The company's success among the younger target group proves that it [i.e. the company] has changed.
Der Erfolg der Firma bei der jüngeren Zielgruppe beweist, dass diese sich verändert hat.
The company's success among the younger target group proves that it [i.e., the target group as opposed to the company] has changed.
In speech, jener is generally rare; in colloquial speech it is even completely avoided (except possibly in some fixed expressions). Instead, one uses forms of dieser and stressed forms of the definite article as demonstrative pronouns, without there being a clear semantic difference between these two. This means that colloquial German does not systematically distinguish between “this” and “that”. When necessary, such a distinction can be expressed by means of the adverbs hier ‎(“here”) and da ‎(“there”): der Mann hier und der Mann da; dieser Mann hier und dieser Mann da (both meaning “this man and that man”).