Definition from Wiktionary, the free dictionary
|Unicode name||KATAKANA LETTER SU|
ス (Hepburn romanization su)
- The katakana syllable ス (su), whose equivalent in hiragana is す (su). It is the thirteenth syllable of the gojūon order, and its position in gojūon tables is サ行ウ段 (SA-gyō, U-dan; “row SA, section U”).
- Unlike the hiragana system, used for Japanese language words that kanji does not cover, the katakana syllabary is used primarily for transcription of foreign language words into Japanese and the writing of loan words (collectively gairaigo), as well as to represent onomatopoeia, technical and scientific terms, and the names of plants, animals, and minerals. Names of Japanese companies, as well as certain Japanese language words, are also sometimes written in katakana rather than the other systems. 
- For a list of words starting with ス (su) see: Special:Allpages/ス