Hal in Tavis's waiting room (p. 524)
'He'll put her in the Show before menses, there'll be another enormous fuss and high-rental cartridges of a girl no larger than her racquet beating up on hairy Slavic lesbians, and then by fourteen she'll be like old coal in the bottom of a backyard grill.' […] 'Clinkers,' he said instantly. 'From klinker low German and klinckaerd old Dutch, to sound, ring, nominated to substantive around 1769: a hard mass formed by the fusion of the earthy impurities of like coal, iron ore, limestone.'
Context
Hal predicts little Tina Echt's burnout, then — asked for the word for spent coal — produces an etymology with the theme buried inside it: a clinker is "a hard mass formed by the fusion of the earthy impurities," and the root means to ring. The junior-tennis machine as a fusion process whose waste product is the player. A sentence later his apple core hits the wastebasket.