drake n.1

mid-13c., dragoun, a fabulous animal common to the conceptions of many races and peoples, from Old French dragon and directly from Latin draconem (nominative draco) "huge serpent, dragon," from Greek drakon (genitive drakontos) "serpent, giant seafish," apparently from drak-, strong aorist stem of derkesthai "to see clearly," from PIE *derk- "to see" (source also of Sanskrit darsata- "visible;" Old Irish adcondarc "I have seen;" Gothic gatarhjan "characterize;" Old English torht, Old High German zoraht "light, clear;" Albanian dritë "light").

Perhaps the literal sense is "the one with the (deadly) glance." The young are dragonets (c. 1300). Fem. form dragoness is attested from 1630s. Obsolete drake (n.2) "dragon" is an older borrowing of the same word, and a later form in another sense is dragoon. Used in the Bible generally for creatures of great size and fierceness; it translates Hebrew tannin "a great sea-monster," and tan, a desert mammal now believed to be the jackal.

narcotic Old World plant, early 14c., mondrake, also mandragge, from Medieval Latin mandragora, from Latin mandragoras, from Greek mandragoras, probably from a non-Indo-European word. The word was in late Old English and Middle English in its Latin form; folk etymology associated the second element with dragoun and substituted native drake in its place, though perhaps with little meaning attached to it. The forked root is thought to resemble a human body and was said to shriek when pulled from the ground. The plant has been regarded as an aphrodisiac.

Meanwhile it should not be forgotten that there was one magical possession, an idol of domestic superstition in mediaeval German households, which is said to have passed at the father's death to the youngest son upon condition that he performed certain heathenish rites in relation to the father's funeral. The "mandrake," a plant with broad leaves and bright yellow flowers and with a root which grew in a semi-human form, was found beneath the public gallows and was dragged from the ground and carried home with many extraordinary ceremonies. When secured it became a familiar spirit, speaking in oracles if properly consulted and bringing good luck to the household in which it was enshrined. [Charles Elton, "Origins of English History," 1882]

multi-colored duck, early 14c. (late 12c. as a surname), from sheld- "variegated" + drake "male duck." The first element probably is cognate with, or from, Middle Dutch schillede "separated, variegated," West Flemish schilde, from schillen (Dutch verschillen "to make different"), from Proto-Germanic *skeli-, from PIE root *skel- (1) "to cut."

This is the origin considered most likely, though English sheld by itself is a dialect word attested only from c. 1500. OED finds derivation from shield (n.), on resemblance to the patterns on shields, "improbable." Compare sheldapple, a 16c. name for types of birds remarkable for variegated plumage (the second element of that might be a variant of alp, an old word for "bullfinch").