There are many terms from classic and modern SF that remain unresearched, and the Historical Dictionary of Science Fiction will be continually updated, especially as additional resources are put online. Boing Boing is syndicating new entries from the HDSF on a regular basis. (Read the series introduction.)
Superheroine, Supervillainess, Martianess
After our recent essay on supervillains, we got a few questions about terms for females with superpowers.
In fact we have had an entry for superheroine in the pipeline for some time, and it's clearly time to publish it. As with superhero, the broader sense 'an extremely heroic woman' is found much earlier, from 1909, and this sense is common through the mid-20th century. It took until 1960 before we have clear evidence of the comics sense 'a woman with superpowers; a female superhero'.
While the comics world has no lack of female villains, the word supervillainess itself took even longer to arise. Its generic equivalent 'an extremely villainous woman' shows up by the 1910s, and also remained in use (Joan Collins's character Alexis Colby on Dynasty often got this descriptor), but the first comics example is only from 1970. It remains relatively uncommon; we expect that the feminine -ess ending makes the term feel inappropriately unthreatening for what it describes.
Finally, while we're on the subject, we're also publishing the word Martianess for a female Martian. This one is much older; Martian is found from the 1860s (the much less common term Marsian is from the 1850s), and the female form arose by the 1890s. It is fairly rare, perhaps because there has not turned out to be much need to describe women from Mars.