also barb wire, "fencing wire with sharp edges or points," 1863, American English; see barb (n.) + wire (n.). Originally for the restraint of animals.
Entries linking to barbed wire
barb n.
late 14c., "barb of an arrow," from Old French barbe "beard, beard-like appendage" (11c.), from Latin barba "beard," from Proto-Italic *farfa- "beard," which might be from a common PIE root *bhardhā- "beard" (source also of Old Church Slavonic brada, Russia boroda, Lithuanian barzda, Old Prussian bordus), but according to de Vaan the vowel "rather points to a non-IE borrowing into the European languages."
wire n.
Old English wir "metal drawn out into a fine thread," from Proto-Germanic *wira- (source also of Old Norse viravirka "filigree work," Swedish vira "to twist," Old High German wiara "fine gold work"), from PIE root *wei- "to turn, twist, plait."
A wire as marking the finish line of a racecourse is attested from 1883; hence the figurative down to the wire. Wire-puller in the political sense is by 1842, American English, on the image of pulling the wires that work a puppet; the image itself in politics is older:
The ministerial majority being thus reduced to five in a house of five hundred and eighty-three, Lord John Russell and Lord Melbourne respectively announce the breaking up of the administration, and the curtain falls on the first act of the political farce, to the infinite annoyance and surprise of the prime wire-puller in the puppet-show. [British and Foreign Review, vol. IX, July-October 1839]