What is a structural turtleneck? It's a sweater so thick and heavy that it can serve as outerwear on its own under most circumstances, or at the most to be layered with an overcoat. Those thin, fine turtlenecks for layering with jackets are essential, but you also want at least one where the neck is robust enough to hold your head up on its own, providing additional whiplash protection when you swerve to avoid some snowboarding punk and make your acquaintance with an evergreen. What architects would refer to as a "load-bearing structure". Goes great with beards and cigarettes.

Shown left to right: J.G.Glover at Sierra Trading Post. Zara. Tom Ford.

Also See