Omega is a Greek letter, which represents the weight in the mathematical weighted average, corresponds to the weight vector and weight matrix in the high number, and also represents the mass fraction of solute in the solution.

The last letter "Ω" in the Greek alphabet originally means "end". When the whole Greek language gradually changed from "oral legend" to "writing", the accurate phonetic corresponding symbol has become an important indicator of the creation and improvement of Greek letters.

Source: @pebbletattoo