Nu in Modern Use

Nu is used in physics chiefly as the symbol for frequency, particularly the frequency of light and other electromagnetic radiation, a convention that has made it one of the more common Greek letters in physics equations despite the letter's otherwise modest ancient profile, covered elsewhere in this atlas. Nu also has a distinctly 21st-century footnote: when the World Health Organization introduced its 2021 system of naming notable coronavirus variants after successive letters of the Greek alphabet, it deliberately skipped both nu and the following letter, xi, when the naming sequence reached them.

The WHO stated at the time that nu was skipped because it could too easily be confused with the English word new in spoken reports, while xi was skipped to avoid association with a common surname, and the next designated variant was instead named Omicron, discussed elsewhere in this atlas. That skip is now probably nu's most widely reported appearance in ordinary news coverage, entirely disconnected from either its ancient Semitic root nun, meaning fish, or its narrow technical use in physics. Astronomers, following the Bayer star-naming convention of 1603, also use Nu to mark a constellation's thirteenth-brightest star.