צָמַם to be pressed together, be restrained.
Hif. - הֵצֵם to restrain; to tie up. Cant. R. to IV, 1 (ref. to צמתך, ib.) האשה הזאת כשמֵצֶמֶּת שערה וכ׳ as a woman ties up her hair behind, and this is an ornament to her, so the Great Sanhedrin sat behind the Temple &c.