Other forms: detours, detoured, detouring
A detour is the longer way round you take when the direct road is shut. Roadworks, a yellow sign, twenty extra minutes through villages you have never heard of.
The verb works too — the bus detoured through the industrial estate — and so does the phrase make a detour. It moves easily off the road: a conversation takes a detour, a career detours into something nobody planned. A detour is not always forced, either; you can make one on purpose to pass a good bakery. British road signs say DIVERSION where American ones say DETOUR, but people in both countries say detour when they speak.
1noundetourA longer route taken because the direct one is blocked or because you want to pass something.
“A burst water main forced a detour through the park.”
synonyms: diversion
2nounmoveA move away from the main subject or plan.
“The talk took a detour into a long story about his father.”
3verbdifferentTo go by a longer or different route.
“We detoured past the coast to see the lighthouse.”
detour is a route.
Detour comes straight from French détour, the noun built on détourner, 'to turn away'. English kept the spelling and very nearly the sound. Whether it is a road or a plan, a detour is nothing more than a turning aside.
French
détour
English, today
detour
Built from
French détour, from détourner (“turn away”).
Etymology from Wiktionary, CC BY-SA