The oka, okka, or oke (Ottoman Turkish اوقه) was an Ottoman measure of weight, equal to 400 dirhems (Ottoman drams). Its value varied, but it was standardized in the late empire as 1.2829 kilograms.OED; but Kélékian gives 1.285 kg '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.