from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A mammalian sex chromosome, occurring only in male cells. Cells of females have a pair of X chromosomes while cells of males have an X and a Y.
Named by Nettie Stevens in 1905 using the next letter in sequence following the naming by Hermann Henking in 1890 of the X chromosome. The brief resemblance in the appearance of the X and Y chromosomes to the letters "X" and "Y" respectively during cell division is entirely coincidental. (Wiktionary)