1902, from wind (n.1) + shield (n.). U.S. alternative to British windscreen (which is attested from 1905 in this sense).
Entries linking to windshield
wind n.1
"air in motion," Old English wind "wind," from Proto-Germanic *winda- (source also of Old Saxon, Old Frisian, Middle Dutch, Dutch wind, Old Norse vindr, Old High German wind, German Wind, Gothic winds), from PIE *wē-nt-o‑ "blowing," suffixed (participial) form of root *we- "to blow."
Normal pronunciation evolution made this word rhyme with kind and rind (Donne rhymes it with mind and Thomas Moore with behind), but it shifted to a short vowel 18c., probably from influence of windy, where the short vowel is natural. A sad loss for poets, who now must rhyme it only with sinned and a handful of weak words. Symbolic of emptiness and vanity since late 13c.
I have forgot much, Cynara! gone with the wind. [Ernest Dowson, 1896]
Meaning "breath" is attested from late Old English; especially "breath in speaking" (early 14c.), so long-winded, also "easy or regular breathing" (early 14c.), hence second wind in the figurative sense (by 1830), an image from the sport of hunting.
Winds "wind instruments of an orchestra" is from 1876. Figurative phrase which way the wind blows for "the current state of affairs" is suggested from c. 1400. To get wind of "receive information about" is by 1809, perhaps inspired by French avoir le vent de. To take the wind out of (one's) sails in the figurative sense (by 1883) is an image from sailing, where a ship without wind can make no progress. Wind-chill index is recorded from 1939. Wind energy from 1976. Wind vane from 1725.
shield n.
Middle English sheld, "frame or rounded plate of wood, metal, etc., carried by an warrior on the arm or in the hand as defense," from Old English scield, scild "shield; protector, defender," originally "board," from Proto-Germanic *skelduz (source also of Old Norse skjöldr, Old Saxon skild, Middle Dutch scilt, Dutch schild, German Schild, Gothic skildus), from *skel- "divide, split, separate," from PIE root *skel- (1) "to cut."
The IE sense evolution of that proposal is uncertain; the ancient notion is perhaps a flat piece of wood made by splitting a log, but Boutkan writes, "it seems more probable to me that the word designated a means of protection, i.e. a separation between the fighter and the enemy."
Shield usually meant a larger defensive device, covering much of the body, as opposed to a buckler. Shield volcano (1911) translates German Schildvulkan (1910). The plate tectonics sense of shield as "large, stable mass of Achaean rock forming a continental nucleus" is by 1906, translating Suess (1888).