"a plane curve with a characteristic 'figure-eight' shape consisting of two loops that meet at a central point," 1811, from Late Latin lemniscus "a pendent ribbon," from Greek lēmniskos "woolen ribbon, woolen tape," perhaps originally or literally "of Lemnos," the island in the Aegean, but if so the reason is obscure. Related: Lemniscate (adj.), 1781.
<a href="https://www.etymonline.com/word/Lemnos">Etymology of Lemnos by etymonline</a>
Harper, D. (n.d.). Etymology of Lemnos. Online Etymology Dictionary. Retrieved $(datetime), from https://www.etymonline.com/word/Lemnos