pike: English has two pikes now in common usage, which are probably ultimately the same word. Pike ‘spear’ [OE] goes back to an Old English pīc ‘pointed object’, which is closely related to English peak and pick ‘sharp implement’. It had various specific applications in Old and Middle English, now long defunct, including ‘pickaxe’, ‘spike’, ‘thorn’, ‘point of a shoe’, and ‘pitchfork’ (and pitchfork [13] itself was originally pickfork, a fork with ‘sharp points’; its current form, which emerged in the 16th century, is due to the association with ‘pitching’ or tossing hay on to a cart).
But the sense ‘weapon consisting of a long pole with a spike on top’ did not appear until the 16th century, partly inspired by the related Old French pique ‘pike’. Pike the fish [14] was probably also named with the descendant of Old English pīc, in allusion to its long pointed jaws (a similar inspiration can be seen in French brochet ‘pike’, a derivative of broche ‘spit’). => peak, pick, pitchfork
pike (n.1)
"highway," 1812 shortening of turnpike.
pike (n.2)
"weapon with a long shaft and a pointed metal head," 1510s, from Middle French pique "a spear; pikeman," from piquer "to pick, puncture, pierce," from Old French pic "sharp point or spike," a general continental term (Spanish pica, Italian picca, Provençal piqua), perhaps ultimately from a Germanic [Barnhart] or Celtic source (see pike (n.4)). Alternative explanation traces the Old French word (via Vulgar Latin *piccare "to prick, pierce") to Latin picus "woodpecker." "Formerly the chief weapon of a large part of the infantry; in the 18th c. superseded by the bayonet" [OED]; hence old expressions such as pass through pikes "come through difficulties, run the gauntlet;" push of pikes "close-quarters combat." German Pike, Dutch piek, Danish pik, etc. are from French pique.
pike (n.3)
"voracious freshwater fish," early 14c., probably short for pike-fish, a special use of pike (n.2) in reference to the fish's long, pointed jaw, and in part from French brochet "pike" (fish), from broche "a roasting spit."
pike (n.4)
"pick used in digging," Middle English pik, pyk, collateral (long-vowel) form of pic (source of pick (n.1)), from Old English piic "pointed object, pickaxe," perhaps from a Celtic source (compare Gaelic pic "pickaxe," Irish pice "pike, pitchfork"). Extended early 13c. to "pointed tip" of anything. Pike, pick, and pitch formerly were used indifferently in English. Pike position in diving, gymnastics, etc., attested from 1928, perhaps on the notion of "tapering to a point."