Many new TVs come with a nit rating, such as the new Samsung HDR (High Dynamic Range) TV, which has 1,000 nits. Computer LCD screens emit up to around 300 nits. The term nit is believed to come from the Latin word nitere, to shine.
A nit is defined as a unit of light intensity and one nit is equal to one candela per square meter. A candela is the amount of light produced by one candle. Bottom line for TV watching, more nits equals brighter brights and darker blacks.