Final answer:
Norman Lockyer discovered helium in the solar spectrum in 1868, and it is the gas commonly used in balloons and the second-most abundant element in the universe.
Step-by-step explanation:
The element that Norman Lockyer discovered in the solar spectrum and named after the Greek word for 'Sun', helios, is helium. This discovery occurred in 1868 when a yellow emission line in the chromospheric spectrum of the Sun was observed, which did not match any known element at the time. Helium is not only recognized for being a light gas used to inflate balloons, but it is also the second-most abundant element in the universe. It was not until 1895 that helium was found on Earth.