Crossword clues for the word: OCTAN The word OCTAN has appeared as an answer to at least 7 crossword clues on different crossword puzzles. Crossword clues for OCTAN Showing 1 to 7 of 7 results Clue(s) Every eighth day Happening every eighth day Occurring every 8th day. Occurring every eight days. Occurring every eighth day. Recurring every eighth day. Recurring on the 8th day.