The oka, okka, or oke (Ottoman Turkish: اوقه) was an Ottoman measure of mass, equal to 400 dirhems (Ottoman drams). Its value varied, but it was standardized in the late empire as 1.2829 kilograms.[1] 'Oka' is the most usual spelling today; 'oke' was the usual contemporary English spelling; 'okka' is the modern Turkish spelling, and is usually used in academic work about the Ottoman Empire.