Romaji (ローマ字, literally, "Roman letters") is the use of Latin script to write the Japanese language.
There are several romaji systems, but this site uses the most popular one Hepburn romanization.
Hepburn romanization (ヘボン式ローマ字 Hebon-shiki Rōmaji) is a system to spell Japanese language using the Latin alphabet. It is used by most foreigners learning or studying to spell Japanese and also studied by the Japanese students in for romanizing personal names, geographical locations, and other information such as train tables, road signs, and official communications with foreign countries.
Hepburn style was developed in the late 19th century by an international commission that was formed to develop a unified system of romanization using mainly English writing conventions and pronounciation is loosely based on English pronunciation for consonants and Italian for vowels.