An Etymological Dictionary of Astronomy and Astrophysics

1. A visible impression or trace on something, as a line, cut, dent, stain, or bruise
   (Dictionary.com).
   

2. To put a mark or marks on.

Etymology (EN): M.E., O.E. mearc, merc “boundary, sign, limit, mark” (cf. O.N. merki “boundary, sign,” mörk “forest” (which often marked a frontier); O.Fr. merke, Goth. marka “boundary, frontier,” Du. merk “mark, brand,” Ger. Mark “boundary, boundary land”), from PIE *merg- “edge, boundary, border;” cf. Pers. marz,
→ frontier.

Etymology (PE): Dâj, variants dâq “brand, marking; hot,” Hamedâni daj “in harvest, the sign placed on a wheat pile indicating not to be touched,” dežan “acid, pungent;” Mid.Pers. dâq, dâk “hot,” dažitan “to burn, scorch,” dažišn “burning;” Av. dag-, daž- “to burn;” cf. Skt. dah- “to burn;” L. fovere “to warm, heat; " Arm. dažan “violent, wild;” Lith. degu “to burn;” O.E. fefor; E. fever. PIE base *dhegh- “to burn.”