spadeyoudaoicibaDictYouDict[spade 词源字典]
spade: English has two words spade, but they are ultimately related. Spade for digging [OE] comes from a Low German source, which also produced Dutch spade. This went back to, or shared a common source with, Greek spáthē ‘broad blade’, which was borrowed into Latin as spatha ‘broad flat instrument’ (source of the English botanical term spathe [18]).

This in turn passed into Italian as spada ‘broad sword’, whose plural spade gave English the playingcard symbol spade [16]. The corresponding French term is épée ‘sword’, adopted by English as a fencing term in the 19th century; and its Old French precursor espee is the ultimate source of English spay [15]. The diminutive form of Latin spatha was spathula, from which English gets spatula [16].
=> spathe, spatula, spay, spoon[spade etymology, spade origin, 英语词源]
spade (n.1)youdaoicibaDictYouDict
"tool for digging," Old English spadu "spade," from Proto-Germanic *spadan (cognates: Old Frisian spada "a spade," Middle Dutch spade "a sword," Old Saxon spado, Middle Low German spade, German Spaten), from PIE *spe-dh-, from root *spe- (2) "long, flat piece of wood" (cognates: Greek spathe "wooden blade, paddle," Old English spon "chip of wood, splinter," Old Norse spann "shingle, chip;" see spoon (n.)).

"A spade differs from a two-handed shovel chiefly in the form and thickness of the blade" [Century Dictionary]. To call a spade a spade "use blunt language, call things by right names" (1540s) translates a Greek proverb (known to Lucian), ten skaphen skaphen legein "to call a bowl a bowl," but Erasmus mistook Greek skaphe "trough, bowl" for a derivative of the stem of skaptein "to dig," and the mistake has stuck [see OED].
spade (n.2)youdaoicibaDictYouDict
black figure on playing cards," 1590s, probably from Italian spade, plural of spada "the ace of spades," literally "sword, spade," from Latin spatha "broad, flat weapon or tool," from Greek spathe "broad blade" (see spade (n.1)). Phrase in spades "in abundance" first recorded 1929 (Damon Runyon), probably from bridge, where spades are the highest-ranking suit.
The invitations to the musicale came sliding in by pairs and threes and spade flushes. [O.Henry, "Cabbages & Kings," 1904]
Derogatory meaning "black person" is 1928, from the color of the playing card symbol.