Ĵ or ĵ (J circumflex) is a letter in Esperanto orthography representing the sound [ʒ].
While Esperanto orthography uses a diacritic for its four postalveolar consonants, as do the Latin-based Slavic alphabets, the base letters are Romano-Germanic. Ĵ is based on the French pronunciation of the letter j to better preserve the shape of borrowings from that language (such as ĵurnalo from journal) than Slavic ž would.
The tittle or superscript dot is the dot on top of lowercase i and j. In English writing the tittle is a diacritic which only appears as part of these glyphs, but diacritic dots can appear over other letters in various languages. In most languages, the tittle of i or j is omitted when a diacritic is placed in the tittle's usual position (as í or ĵ), but not when the diacritic appears elsewhere (as į, ɉ).