I was already aware of its relation to 'ed' (having had to actually use 'ed' in ancient times). However that doesn't change the fact that it does stand for "stream editor".
After reading your post, I thought "That doesn't seem right, I remember it specifically being referred to as 'stream editor'", so I went looking.
Well, according to the man page, it is indeed "stream editor":
https://man.cat-v.org/unix_8th/1/sed
I was already aware of its relation to 'ed' (having had to actually use 'ed' in ancient times). However that doesn't change the fact that it does stand for "stream editor".
After reading your post, I thought "That doesn't seem right, I remember it specifically being referred to as 'stream editor'", so I went looking.