Si
Here is the meaning and Word Scramble Game information for Si
SI2 is a valid Scrabble Word in NWL, formerly TWL (USA, Thailand, Canada)
SI2 is a valid Scrabble Word in CSW, formerly SOWPODS (Other Countries)
SI2 is a valid word in WWF
() A syllable applied, in solmization, to the note B; more recently, to the seventh tone of any major diatonic scale. It was added to Guido's scale by Le Maire about the end of the 17th century.