E621, the E number for Monosodium glutamate
Monosodium glutamate, commonly known as MSG, is a widely used flavor enhancer in the food industry. For many years it has been associated with different health problems, making it a controversial ingredient. However, recently E621 has become an accepted additive in many countries due to scientific studies that have found its consumption safe.
E621, a E6 Series Shinkansen locomotive car
The E6 series (E6系) is a Japanese Shinkansen high-speed train operated by East Japan Railway Company.
FS Class E.621, an Italian locomotive class
621 was a class of five electric locomotives of the Italian State Railways (FS). They were rebuilt in 1947 from FS Class E. 620, originally built in 1925. The main change was a conversion from a 650 V DC third rail to a 3,000 V DC overhead line power supply.
e621, a booru-style imageboard focusing on the furry fandom, owned by Bad Dragon
Furbooru is a furry image board focused on the fandom that was launched on April 24, 2020.