sandpaper n.

"water-worn detritus finer than gravel; fine particles of rocks (largely crystalline rocks, especially quartz); the material of the beach, desert, or sea-bed;" Old English sand, from Proto-Germanic *sandam (source also of Old Norse sandr, Old Frisian sond, Middle Dutch sant, Dutch zand, German Sand), from PIE *bhs-amadho- (source also of Greek psammos "sand;" Latin sabulum "coarse sand," which is the source of Italian sabbia, French sable), suffixed form of root *bhes- "to rub."

Historically, the line between sand and gravel cannot be distinctly drawn. Used figuratively in Old English in reference to innumerability and instability. General Germanic, but not attested in Gothic, which used in this sense malma, related to Old High German melm "dust," the first element of the Swedish city name Malmö (the second element meaning "island"), and to Latin molere "to grind."

Metaphoric for innumerability since Old English. In compounds, often indicating "of the shore, found on sandy beaches." In old U.S. colloquial use, "grit, endurance, pluck" (1867), especially in have sand in (one's) craw. Sands "tract or region composed of sand," is by mid-15c.

mid-14c., "material consisting of a compacted web or felting of vegetable fibers, commonly as a thin, flexible sheet for writing, printing, etc.," from Anglo-French paper, Old French papier "paper, document," and directly from Latin papyrus "paper, paper made of papyrus stalks," from Greek papyros "any plant of the paper plant genus," a loan-word of unknown origin, often said to be Egyptian (see papyrus).

Sense of "essay, dissertation on a topic" is from 1660s. Meaning "bills of exchange, paper money" is attested by 1722. As "paper for covering the walls of interiors," 1764. As "printed sheet of news" (a shortened form of newspaper), attested by 1640s. Papers, "collection of documents which establish one's identity, standing, credentials, etc.," it is attested from 1680s.

Paper-clip is by 1875; paper-cutter as a type of machine is by 1969. Paper-hanger is by 1796. Paper-wasp " type of wasp that builds a nest out of paper-like material" is by 1805. Paper chase is by 1856 in British English for the game of hare-and-hounds, from the bits of paper scattered as "scent" by the "hares;" the slang meaning "effort to earn a diploma or college degree" is by 1932.