The changing seasons and falling leaves are a great time to ponder life's great questions.

"Is it a shirt or is it a jacket?" is not one of those great questions.

But still, the beguiling overshirt, shirt jacket or shacket, if you're into portmanteaus, should be a go-to option for staying just the right amount of warm throughout fall and winter.   

These are 10 shirt jackets for your consideration. Wear them, layer them, love them.

The Blanket Flannel Field Jacket combines vintage military style with heavyweight double-brushed flannel. Buck Mason, $158

Here's a quilted wax canvas shirt jacket that will never go out of style. It's tough, versatile and ready for anything. Flint and Tinder, $258

Throw on a Blanket Shirt, and you just know you're going to be cozier than the next guy. The best part: You can choose from almost 50 (!) different styles. Outerknown, $148

This hardworking shirt is made from a machine washable Italian merino wool blend. Interior detailing keeps things interesting when you wear it open, and hand warmer pockets are ready for you on cold days. Topo Designs, $169

Shirt jackets come in multiple styles, as evidenced by this four-pocket, camp collar shirt with blazer-like sensibilities. It's made from lightweight brushed cotton flannel for extra softness. Ralph Lauren, $90

Here's a linen-cotton option that's insulated with recycled poly fill for added warmth. Add some fine detailing, like a leather locker loop and antique brass snaps, and you'll look better than you have to. Billy Reid, $198

This rugged Shop Shirt is made from a performance hemp blend and is stonewashed for a broken-in look and feel from day one. Pair it with some dark denim, and wear it to work, rake leaves or teach a shop class. Taylor Stitch, $168

Faherty's Legend Sweater Shirt is available in more than a dozen patterns, but we're partial to this handsome number featuring a design from Native artist Doug Good Feather. Faherty, $178

Reach for this sweater-like fleece shirt whenever temperatures dip. It’s made from extra-soft recycled performance fabric that offers lightweight warmth in cool weather. Peter Millar, $168

This 100% cotton textured corduroy shacket is cut with a relaxed silhouette, so it's easy to throw it over a T-shirt or heavier layers. Abercrombie & Fitch, $68