A flurry of feathers. A cluster of blossoms and wisps. A gathering of tulle, rhinestones, berries, or quills tucked into tresses. They're called fascinators. And these days, they offer a welcome bit of flirtatious diversion.

Let's begin with a definition. While there's no rule as to their design or composition, the whimsical pieces must live up to their name.

"It's got the name because it's fascinating to look at," says Boston-based milliner Marie Galvin, noting that any observer should be rightfully "mesmerized" by the hair accessories. According to Galvin, the combination of materials is endless. "As long as there's some sort of swirly movement," she says, anything goes.