Likely related to Hbr. ŝkl pi. ‘to lay over crosswise (one’s hands)’, Arb. škl ‘to bind the beast with the rope called šikāl’, III ‘to be comfortable, suitable, similar, congeniaľ, Jib. ŝɔ́tkel ‘to be stuck to one another’. The original basic meaning is, presumably, ‘to be in front each other, to correspond, to fit’. The Soqotri term for ‘twins’ (ŝέkľi) and its MSA cognates (ML 378) also belong here. Contra Leslau (LS 416), unrelated to škeḷ ‘to cover’.