The symbol "Ω" represents the unit of electrical resistance known as the Ohm. It measures how much a material opposes the flow of electric current. A higher resistance means less current can flow for a given voltage, according to Ohm's Law, which states that voltage equals current times resistance (V = I × R). The Ohm is named after the German physicist Georg Simon Ohm, who formulated the relationship between voltage, current, and resistance in the 1820s. This unit is essential in electrical engineering and physics, helping to design and analyze electrical circuits effectively.