Mathematical Bold Small Omega

With amsmath, use \boldsymbol{\omega} in math mode.

That command produces formatted math, not the literal Unicode character 𝛚.

In physics and applied math, bold lowercase letters commonly denote vectors; elsewhere, bold weight may simply distinguish variables. The formula’s key tells you which convention applies.

Where did omega come from?

It was a later Greek addition for the long O vowel.

Greek writing adapted Phoenician letter forms, but omega was added later in Ionia, Greek cities along the eastern Aegean. The Ionic alphabet formed it by opening omicron’s O shape and used it for a long O vowel. It is attested from the second half of the seventh century BCE; Athens adopted Ionic for official writing in 403/2 BCE.

In modern Greek, omega and omicron both spell the /o/ sound; the old length distinction is gone from speech but preserved in spelling. Omega is the Greek alphabet’s last letter, so “alpha and omega” in the Book of Revelation pairs its first and last letters with the beginning and end. That Christian reading belongs to the Greek letter, not a fixed value for 𝛚 in a formula.