(Fe)male

Female v. Male

(source)

The tricky thing about historical linguistics is that things are not always as they seem. A folk etymology (aka fake etymology) of these words might have you believing that female is a derivative of male or vice versa. In reality, the fact that these words have a similar form in English is a coincidence. Female dates to the early 14th century from Old French femelle ("woman, female"), which derives from Middle Latin femella (" female"), which is based on the Latin diminutive of femina ("woman"), femella ("young female, girl"). It ultimately derives from Proto-Indo-European *dhei- ("to suck, suckle" or "produce, yield"). Male also dates to the 14th century and comes from Old French, but it appears decades later than female and the word it comes from is masle. Masle derives from Latin masculus ("masculine, male"), which is the diminutive of mas ("male person or animal, male")