An Etymological Dictionary of Astronomy and Astrophysics

Running continuously around a fixed point or center while constantly receding from or approaching it.

Etymology (EN): From M.Fr. spiral, from M.L. spiralis “winding, coiling,” from L. spira “coil,” from Gk. speira “coil, twist, wreath.”

Etymology (PE): Mârpic, literally “snake coil,” from mâr “snake, serpent,” → Serpens, + pic, present stem of picidan “to twist, entwine, coil,” ultimately Proto-Iranian *paticā-citanai- “to coil;” cf. Av. paitica “inversely; back” and ci- (caē-, caii-) “to heap up, gather” (Nyberg 1974).