The phrase does not point to one single picture only.
Olam ha-ba means the world to come
Britannica defines olam ha-ba as either the world after death or the restored world that follows messianic redemption.
That ambiguity matters. Jewish theology has not always reduced the concept to one flat model of heaven.
The term is set against this world
Britannica also notes the contrast with olam ha-ze, this world. Present life is the arena in which one becomes worthy of the world to come.
That contrast helps explain the ethical use of the concept. Olam ha-ba is not only speculative belief. It shapes how this life is judged.
Why it still matters
Olam ha-ba still matters because it gives Jewish theology a language for hope, judgment, and ultimate repair without collapsing all meaning into present circumstances.
The shortest accurate answer
Olam ha-ba is the Jewish idea of the world to come, referring either to life after death or to the restored world of redemption.