סִיּוּם, (סוּם I, Pi.) conclusion, finishing. Tanḥ. Haăz. 5 ס׳ חתימתו וכ׳ the final letter of Moses’ signature. Ib. כאדם … וחותם … בס׳ ספרו like a man that finishes his book and signs his name (in an acrostic) at the end of his book.