Where does “blastula” come from?

blastula (New Latin) comes from Ancient Greek βλαστός, from Ancient Greek -τός, from Proto-Indo-European -tós — Creates verbal adjectives from verb stems.

Ancestry of “blastula”, step by step

Step	Language	Word	Meaning
1	Ancient Greek	βλαστός	sprout, shoot, bud; offspring, scion
2	Ancient Greek	-τός	creates verbal adjectives of possibility, either...
3	Proto-Indo-European	-tós	Creates verbal adjectives from verb stems

Every word from Proto-Indo-European -tós →