"cutter that removes wood from a groove," 1818, from rout "poke about, rummage" (1540s), originally of swine digging with the snout; a variant of root (v.1).
Entries linking to router
root v.1
"dig with the snout," 1530s, wroot, of swine, from Middle English wroten "dig with the snout," from Old English wrotan "to root up," from Proto-Germanic *wrot- (source also of Old Norse rota, Swedish rota "to dig out, root," Middle Low German wroten, Middle Dutch wroeten, Old High German ruozian "to plow up"), from PIE root *wrod- "to root, gnaw."
Altered by association with root (v.3), as if "to dig up by the roots." Extended sense of "poke about, pry" is recorded by 1831. The picturesque phrase root hog or die "work or fail" first attested 1834, American English (in works of Davy Crockett, who noted it as an "old saying").