An Etymological Dictionary of Astronomy and Astrophysics

1. A mark or stroke long in proportion to its breadth, made with a pen, pencil, or other tools.
   

2. Math.: A continuous extent of length, straight or curved, without breadth or thickness; the trace of a moving point.

Etymology (EN): M.E. li(g)ne “cord, rope, stroke, series,” from O.E. line “rope, row of letters,” partly from O.Fr. ligne, from L. linea “linen thread, string, line,” from phrase linea restis “linen cord,” from fem. of lineus (adj.) “of linen,” from linum “flax, linen.”

Etymology (PE): Xatt, xat, used also in Ar., but it has no Hebrew counterpart. Xat is probably of Iranian origin, from
*kerš-/*xrah- “to draw, plow;” cf. Av. karš- “to draw; to plow,” karša- “furrow;” Mid/Mod.Pers. kešidan, kašidan “to draw, protract,
trail, drag, carry,” dialectal Yaqnavi xaš “to draw,” Qomi xaš “streak, stria, mark,” Lori kerr “line;”
cf. Skt. kars-, kársati “to pull, drag, plow;”
Gk. pelo, pelomai “to move, to bustle;” PIE base k^wels- “to plow.”