I think a number of the example answers are mystifying meaning. In my view, meaning is simply the answer to the question “why is life worth living?”. It is thus a very personal thing, what is meaningful for one mind may be utterly meaningless to another.
Yet as we are all humans, some significant overlap in the sorts of things that provide a sense of reason or gladness to being alive exists.
I will quote my favorite song, “The Riddle” by Five for Fighting, which gives two answers: “there’s a reason for the world, you and I” and “there’s a reason for the world, who am I?”
I think these capture the two most common sources of meaning for people. Our interactions, love and care for others is one major aspect of what, for many, makes life worth living. And the other is looking inside oneself, finding the things you cherish for their own sake and the moments of flow and joy you are able to find in the world.
I think a very interesting aspect of this idea is that it explains why it can be so hard to come up with truly original ideas, while it is much easier to copy or slightly tweak the ideas of other people. Slight tweaks were probably less likely to get you killed, whereas doing something completely novel could be very dangerous. And while it might have a huge payoff, everyone else in the group could then copy you (due to imitation being our greatest strength as a species) so the original idea creator would not have gained much of a comparative advantage in most cases.