Grind

amolar

(to remove material by rubbing with an abrasive surface)

brunir

(to shape with the force of friction)

moer

(to reduce to smaller pieces)

polir

(to shape with the force of friction)

ralar

(to work or study hard)

ranger

(to move with much difficulty or friction)

rangir

(to move with much difficulty or friction)

rebolar

(slang: to rotate the hips erotically)

triturar

(to reduce to smaller pieces)