We don't have synonyms for oktas yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are okta, okas and ktas.
(n) :
(meteorology) One eighth of the total area of the celestial dome; used as a measure of cloudiness (one okta means that one eighth of the sky is obscured, two oktas that one quarter is obscured, and so on).
(n) :
(meteorology) One eighth of the total area of the celestial dome; used as a measure of cloudiness (one okta means that one eighth of the sky is obscured, two oktas that one quarter is obscured, and so on).