When coeducational colleges were still a novelty, female students at such colleges were often referred to as "coeds." As the '60s became the '70s, and the '70s became the '80s, the word did not age well. The term became virtually meaningless as same-sex schools became increasingly rare. Its use was ironic at best, sexist at worst, and the seemingly obvious original meaning got lost as people referred to women at non-coeducational schools as "Wellesley coeds" and "Barnard coeds."
I've used the word as a throwaway inclusion in copy-editing tests, including my contribution to this year's test for Washington Post copy-editing internships. This time it wasn't such a throwaway, as almost all the applicants let it stand. Only one flagged it with the red-pencil equivalent of the gasp it deserved. When I saw these results, a day after hearing a television reference to "coeds" that further eroded the original meaning by referring to students of both sexes, I started to think the word might be making a comeback.
The legitimate meaning of the word makes it difficult to use databases to gauge whether such a comeback is under way, but I implore you help me to nip this, if there is a "this," in the bud.