An Etymological Dictionary of Astronomy and Astrophysics

Abrasive particles or granules, classified into predetermined sizes, typically of Silicon Carbide or Aluminum Oxide, used between the mirror and tile tool to grind the glass.

Etymology (EN): Grit, from O.E. greot “sand, dust, earth, gravel,” from P.Gmc. *greutan “tiny particles of crushed rock” (cf. O.S. griot; O.N. grjot “rock, stone;” Ger. Grieß “grit, sand”); PIE base *ghreu- “to rub, pound, crush.”

Etymology (PE): Šen “sand, grit.”