From an unused root perhaps meaning to be hollow; a culvert -- gutter, water-spout.
H6794. tsinnuwr
צִנּוֺר noun masculine pipe, spout, conduit (so Late Hebrew); — absolute בַּצִּנּוֺר וְיִגַּע 2 Samuel 5:8 (i.e., si vera lectio, of Jerusalem, but very dubious, compare Dr HPS); plural suffix צִנּוֺרֶיךָ קוֺל Psalm 42:8 the sound of thy (water-) spouts figurative, of sluices of heaven opened, compare מֶּלֶג אֲרֻבֶּה,.