(Latin: to chew; Greek: to gnash, grind, or rub the upper and lower teeth together)

(Greek: friction, rub, rubbing, grind, wear away; spend, waste time; be busy)

(Greek: to crush; to massage, to rub, rubbing, friction, to grind)

(Latin: to rub; to thresh, to grind; to wear away; from tritus, past participle of terere, "to rub")