"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.
type of shoe consisting of a sole fastened to the foot by thongs, the common footwear of ancient Greece and Rome, late 14c., from Old French sandale and directly from Medieval Latin sandalum, from Latin sandalium "a slipper, sandal," from Greek sandalion, diminutive of sandalon "a sandal," also "a flatfish," a word of unknown origin, probably foreign, perhaps from Persian. Related: Sandals.
1510s, earlier simply sandell (late 14c.), saundres (early 14c.), "the wood of the heart and roots of certain species of trees native to Asia," from Old French sandale, from Medieval Latin sandalum, from Late Greek santalon, which is ultimately from Sanskrit čandana-m "the sandalwood tree," perhaps literally "wood for burning incense," related to candrah "shining, glowing," and cognate with Latin candere "to shine, glow" (see candle). In China it was burnt extensively as incense in temples and homes. Sandalwood oil, distilled from the wood of some species, is strongly aromatic and used in perfumes and cosmetics.
also sand-bag, 1860, "furnish (a riverbank, etc.), with sandbags," from sandbag (n.).
The meaning "pretend weakness" is by 1970s perhaps extended from the poker-playing sense of "refrain from raising at the first opportunity in hopes of raising more steeply later" (1940), which perhaps is from sandbagger in the sense of "bully or ruffian who uses a 'sandbag' (in the sense of a cosh or sap) as a weapon to knock his intended victim unconscious" (1882). Hence "to fell or stun with a blow from a sandbag" (1887). Related: Sandbagged; sandbagging.
also sand-blind, "half-blind, partially blind, dim-sighted," c. 1400, probably altered (by influence of unrelated sand (n.), perhaps as though "having grit in the eyes"), from Old English *samblind, with blind (adj.) + first element from West Germanic *sami-, from PIE *semi- (see semi-).
Now archaic or obsolete. Compare Old English samlæred "half-taught, badly instructed," samstorfen "half-dead," also later sam-hale "in poor health," literally "half-whole;" sam-sodden "half-cooked." Also compare purblind.