Chinese Starbucks Sizes
From the Starbucks webpage, I figure it's 杯 /bei/， meaning "cup".


Short: 小杯 /xiǎo bēi/ (small cup)
Tall: 中杯 /zhōng bēi/(medium cup)
Grande: 大杯 /dà bēi/ (large cup)
Venti: 超大杯 /chāo dà bēi/ (extra large cup)