A root is the part of a plant that grows underground, or the origin of something: "the root of the problem." A route is a way of getting from one place to another: "the quickest route to the station." If you can travel along it, it is a route; if it is a source or a foundation, it is a root.
The core difference
Root points downwards and backwards — to origins, foundations and sources. Route points forwards — to a path taken from A to B. The confusion is partly one of pronunciation, which varies more than most people expect.
Using root
- The tree's roots had lifted the pavement.
- We need to get to the root cause, not treat the symptoms.
- She still has roots in the village where she grew up.
- The square root of 81 is 9.
- The word has a Latin root.
Root is also a verb, in several senses: pigs root about in the earth, an idea can be rooted in tradition, and you can root out corruption. In American English, to root for a team means to support it — British speakers usually say cheer on.
Using route
- The bus takes a different route on Sundays.
- We're en route to the airport.
- Applying through an agency is the usual route into the industry.
- Calls are routed through the switchboard.
Note the figurative use in the third example: a route can be a way of achieving something as well as a physical path.
The test
Ask whether you could put along or via in front of it. "Along the route" and "via a different route" both work; "along the root" does not, unless you are literally tracing a plant. If instead you could substitute source, origin or base, you want root.
Pronunciation, which is where this gets slippery
In British English, route rhymes with boot, exactly as root does — which is why the two are so easily confused in writing. In much of the United States, route is often pronounced to rhyme with out, so "Route 66" and "root" sound quite different there. Both American pronunciations are standard, and speakers frequently use both.
The networking device follows the same split: British speakers say rooter, many American speakers say rowter. Neither is wrong.
The edge cases
Watch for rout, no e: a decisive defeat, or to defeat comprehensively — "the match ended in a rout." It rhymes with out everywhere. Confusingly, rout out and root out are both used to mean to dig out or expel; root out is the safer choice in modern writing.
And en route keeps its French spelling and its two words: not on route, and not enroute in careful British usage.
Frequently Asked Questions
Is it 'root cause' or 'route cause'?
Root cause. The phrase means the underlying origin of a problem, the thing everything else grows from, so it takes the plant word. 'Route cause' is a misspelling.
Is it 'en route' or 'on route'?
En route — it is a French phrase meaning on the way, and English has kept the original spelling. Write it as two words; 'on route' is a mishearing and looks careless in formal writing.