"quality assurance" comes from testing, where you're checking to make sure the product is quality, to make sure development actually produced quality code.
quality comes from 1000s of little things you and your team do, when creating software.
some times that involves development. testing plays a role (albeit a very small one)
but quality, quality assurance, whatever you want to call it , is much much more than just code and test
"quality assurance" comes from testing, where you're checking to make sure the product is quality, to make sure development actually produced quality code.