ASCII Character сCyrillic small letter es
Es (С с; italics: С с) is a letter of the Cyrillic script. It commonly represents the voiceless alveolar fricative /s/, like the pronunciation of ⟨s⟩ in "sand". The Cyrillic letter Es is derived from a variant of the Greek letter Sigma known as lunate sigma (Ϲ ϲ), in use in the Greek-speaking world in early medieval times. It has no connection to the Latin letter C (C c), which is a descendant of the Greek letter Gamma (Γ γ); however, many languages (for different reasons) apply the value of /s/ to the Latin letter C, especially before front vowels e and i (examples being English, French, Mexican Spanish); see hard and soft C. As its name suggests, Es is actually related to the Latin S.