We are currently seeking the originator of the term “fictional other / F/O” for historical preservation purposes.

It appears that the term was coined on Tumblr, in the late spring or more likely early summer of 2017.

The earliest post we have yet found that uses the term is from July 1, 2017.

Looking through the archives of self ship blogs that were active at the time we see that in June of 2017 many people were reblogging “imagine your fave” posts, and in August of 2017 these same blogs were reblogging “imagine your F/O” posts.