Perhaps related to GermanEcke(“corner”) with some locative ending or tool-suffix (probably not the root of Saal), compare GermanAchselhöhle(“armpit”).
This etymology is missing or incomplete. Please add to it, or discuss it at the Etymology scriptorium. Particularly: “Less likely related to σῠ́νᾰψῐς(súnapsis, “point or line of junction”), which is not certainly related with Ancient Greek ἰᾰ́πτω(iáptō) and Latin iaciō), and not related to junction either (compare Jochbein(“cheekbone”); as for the vocalism, see Old High German ir(“you”) or French Yves(literally “yew”)), nor nasal spirant lost from Angel (cp. Dutch IJssel, perhaps "furrow"; Old Norse eggja(“to incite”), cp. ängstigen(“to scare”)), nor specialization from aequus (as in Tag-und-Nacht-Gleiche(“equinox; pass-over”), ...?”
Ixel on the German Wikipedia.Wikipedia de