Omega

Omega is the last letter of the Greek alphabet, and its name means “big O”, to tell it apart from omicron, “little o”. Being last, it stands for the end of things, paired with alpha in the Christian title “the Alpha and the Omega”.

In electronics Ω is the ohm, the unit of electrical resistance, named after the German physicist Georg Ohm. Unicode has a separate ohm sign, kept only for compatibility with older character sets, and recommends this Greek letter instead.