A lowercase Greek letter commonly used to denote angular frequency, last elements in sequences, or specific differential forms.
Examples
Angular frequency in physics
\omega = 2\pi f
Last element in a sequence
x_1, x_2, \ldots, x_\omega
Sample space in probability
P(\omega) = \sum_{i=1}^n P(E_i) \text{ where } \omega \in \Omega