Ĉ or ĉ (C circumflex) is a consonant in Esperanto orthography, representing the sound [t͡ʃ].
It is based on the letter c. Esperanto orthography uses a diacritic for all four of its postalveolar consonants, as do the Latin-based Slavic alphabets. Letters and digraphs that are similar to ĉ and represent the same sound include Slovene č, Polish digraph cz, English and Spanish digraph ch, French trigraph tch, Norwegian trigraph tsj, German tetragraph tsch, and Italian c before i or e.
Ĉ is the fourth letter of the Esperanto alphabet. Although it is written as cx in the x-system and ch in the h-system, it is C with a circumflex (ĉ) when written accented. L. L. Zamenhof, the creator of Esperanto, recommended using ch when ĉ is not available.