The meaning[1] of life, whether you are talking about biological life, a human life, or galactic civilizations, is the same: To become or create their successors. The meaning[2] of this depends on which kind of life.
[1] In the sense of purpose or goal.
[2] In the sense of fundamental character that is conveyed, especially by language.
Visit EliezerYudkowsky's FAQ about the Meaning of Life.
See other InterestingMemes.