James Coviello dress ($365, Proper Topper, 1350 Connecticut Ave. NW; 202-842-3055)

In BBC’s “Sherlock,” actor Benedict Cumberbatch plays a hip, modern version of Arthur Conan Doyle’s sleuth who notably spurns wearing one of those infamous flapped tweed hats. His character may resist the siren call of the warm, woolly fabric, but designers can’t get enough of it this fall. The woven material, which traces its lineage to the hills of Scotland and Ireland, is now starring in shapely dresses, shoes and, of course, a toasty blazer or two.

In the British Isles, tweed got its name not from the river Tweed, but from a mispronunciation of the word twill. (Try saying it with a Highland lilt and you’ll understand.)

Then, as now, the stuff was prized for its warmth and durability. “Tweed is like the hot toddy of fashion, plus it’s got this speakeasy feel,” says Holly Bass, a D.C. performance artist and one of the founders of the annual Tweed Ride, a retro-style bike trip last Sunday that sent wool-fedora-wearing dandies and women in herringbone skirts pedaling vintage bikes through downtown.

Boden jacket ($224, Bodenusa.com)

Coco Chanel was the first designer to vault tweed from English hunting clubs into high fashion, turning it into wool suits beginning in the 1920s. Now, to keep it from feeling too fusty and professorial, tweed works well as a mix-in: a jacket with jeans, James Coviello’s slate-hued sheath sparked with a neon lace undershirt.

“Tweed’s got a historic edge that lets you take it daring, edgy places,” says Anna Fuhrman, owner of Dupont Circle boutique Proper Topper, which stocks Coviello looks.

The material’s different yarns can make for some wild checks and intense plaids. “But tweed has so many colors, it goes with everything,” says designer Joeffer Caoc, whose biker jacket-gone-corporate (sold locally at Betsy Fisher) mixes sleek nylon with traditional tweed. It’s a look so sexy and tough, even Sherlock might be swayed.