See the entire entry for ṣīr, ṣīrā n.m. hinge, pivot

TN Ex26:17 :תרין צירין ללוחא חדתא משלוושין דא לקבל דא : There shall be two hinges for each plank, being bolted one to the other

See the entire entry for šlbš vb. to bolt or link together