にち【日】 : nichi | define meaning

Cognate with standard Japanese にち【日】 nichi "day (of the month)". Ultimately from Chinese 【日】 "sun; day" (cf. Mandarin rì; Mandarin jat6; Eastern Min nĭk; Hokkien li̍t, le̍t, ji̍t and gi̍t; Sino-Korean 일 il; Sino-Vietnamese nhật and nhựt), reconstructed for Middle Chiense as *nyit.

Historical Ryukyuan attestations

• Vocabulary of the language spoken at the Great Loo-Choo Island, in the Japan Sea (1818), by Herbert John Clifford, records "Day (at Napakiang). Nit'chee. † The day at Loo-Choo is divided into six hours, as also the night. In counting a number of days they apply the numerals in a similar manner to that which will be found in a note on Twitchee, an hour; but they did not seem to have any names to denote the days of the week".