digamma
/daɪˈgæmə/ 17a letter of the Greek alphabet (Ϝ) that became obsolete before the classical period of the language. 古希腊字母 (Ϝ)
noun [专属名词]早期希腊语的第六个字母，古希腊字母的Ｆ
a letter of the original Greek alphabet representing a sound approximately that of English w which early fell into disuse except in writing the western dialects.
单词造句: