starstuff
The material composition of stars; matter originated from stars; starmatter.
uncountable
Not only is the matter around you star-stuff, but you are, too. There is not a single cell in your body that is not made of matter formed in the heart, and then the death, of a distant and now-extinct star.
Where it comes from
From star + stuff. Compare Dutch sterrenstof (“stardust”), German Sternenstoff (“star matter”).
Adapted from the Wiktionary entry starstuff (CC BY-SA 4.0).