When forming the present participle or verbal noun from the verb to route it is preferable to retain the e in order to distinguish the word from routing, the present participle or verbal noun from rout1, to defeat or rout2, to dig, rummage: the routeing of buses from the city centre to the suburbs. The spelling routing in this sense is, however, sometimes encountered, esp in American English
C13: from Old French rute, from Vulgar Latin rupta via (unattested), literally: a broken (established) way, from Latin ruptus broken, from rumpere to break, burst
1598, "disorderly retreat," from M.Fr. route "disorderly flight of troops," lit. "a breaking off, rupture," from V.L. rupta "a dispersed group," lit. "a broken group," from L. rupta, fem. pp. of rumpere "to break" (see rupture). The verb is from 1600.
early 13c., from O.Fr. rute "road, way, path," from L. rupta (via) "(a road) opened by force," from rupta, fem. pp. of rumpere "to break" (see rupture). Sense of "fixed or regular course for carrying things" (cf. mail route) is 1792, an extension of the meaning "customary path of animals" (early 15c.).
tool /row'ting/ Using a kind of rotating cutting tool called a router, pronounced /row't*/. In the USA a router, pronounced /row't*/, is also a network device that performs "routing". In the UK, the network device is pronounced /roo't*/ and what it does is spelled "routeing". (2002-07-31)