"tool for digging," Old English spadu "spade," from Proto-Germanic *spadan (source also of Old Frisian spada "a spade," Middle Dutch spade "a sword," Old Saxon spado, Middle Low German spade, German Spaten), from PIE *spe-dh-(source also of Greek spathē "wooden blade, paddle"), which as a suffixed form has been grouped under a root *speh-, "with several extensions, denoting quite different implements" (Boutkan) but basically indicating "long, flat piece of wood" (source also of 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 skaphē "trough, bowl" for a derivative of the stem of skaptein "to dig," and the mistake has stuck [see OED].

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.

early 15c., "stab with a sword, kill," also "remove the ovaries of (a hunting dog)," from Anglo-French espeier "cut with a sword," Old French espeer, espaer, from espee "sword" (Modern French épée), from Latin spatha "broad, flat weapon or tool," from Greek spathē "broad blade" (see spade (n.1)). Related: Spayed; spaying.

1590s, intransitive, "dig a covered trench toward the enemy's position," from French saper, from sappe "spade," from Late Latin sappa "spade, mattock" (source also of Italian zappa, Spanish zapa "spade"), which is of unknown origin. The transitive sense of "undermine (a wall, etc.), render unstable by digging into or eating away the foundations" is from 1650s.

The extended transitive sense (of health, confidence, etc.), "weaken or destroy insidiously," is by 1755 and perhaps has been influenced or reinforced in sense by the verb form of sap (n.1), on the notion of "draining the vital sap from," and later by sap (v.2) "beat with a club or stick."

It also sometimes is used as a noun, "a narrow, covered ditch or trench by which a fortress or besieged place can be approached under fire" (1640s). Sap (n.) in the "tool for digging" sense also occasionally is met in 16th century English. Related: Sapped; sapping.

"wooden shovel with a broad blade and a long handle," used by bakers, etc., late 14c.. pele, from Old French pele (Modern French pelle) "shovel," from Latin pala "spade, shovel, baker's peel, shoulder blade," related to pangere "to insert firmly," probably from PIE *pag-slo-, suffixed form of root *pag- "to fasten."

"flat wooden blade" used as a tool by potters, etc., for shaping their wares, early 15c., from Old French palete, diminutive of pale "spade, shovel" (see palette, which is the more French spelling of the same word). The original sense in English was medical, "flat instrument for depressing the tongue." Meaning "large portable tray" used with a forklift for moving loads is from 1921.