While it traces its namesake back to the Chief Petty Officers of the United States Navy -- whose signature collared coats were a bit more formal than those of their peers -- you don't have to be a seasoned seafarer to sport a CPO jacket. This versatile shirt-jacket hybrid burst back onto the fashion scene in the 1960s and has stuck around ever since, albeit in a form a bit removed from its military roots. The CPO jacket backs up its sticking power with a timelessly rugged look and a hearty helping of versatility.

At first glance, the CPO jacket looks like a long-sleeved button-up shirt made of thick flannel. These midweight jackets characteristically feature a single row of large buttons -- often anchor buttons, in honor of the shirt's naval history -- and double, flap-style front chest pockets with buttons, though you may come across the occasional single-pocket garment. Most also have fold-over collars and button cuffs. Less common features include contoured hems, slash pockets and a quilted outer shell.

Most CPO jackets feature a warm, somewhat fuzzy wool shell and a smoother polyester lining or a fluffy sherpa-style interior. The majority of styles come in plaid patterns, including window-pane, gingham and tartan styles, composed of masculine colors, such as burgundy, blue, hunter green, charcoal and taupe. While plaid patterns rule the CPO schoolyard, you can also find solid-colored CPO jackets, which have a subtly classic appeal. Particularly time-tested hues include navy, gray and brown.

The CPO jacket lends itself to all sorts of layering combinations. Worn unbuttoned, it suits the ageless combination of a solid-colored T-shirt and dark-wash jeans, but this shirt-jacket works just as well buttoned up with a pair of jeans or neutral-hued chinos. For cooler climes, you can throw a jacket over your CPO, wearing it like a particularly warm button-up shirt. The cozy CPO shirt works well with a casual scarf, either over the buttoned-up, jacket-style CPO or between the unbuttoned CPO and your underlayer.

As a rule of thumb, if you're sporting a plaid top, contrasting the pattern with a solid-colored underlayer and bottoms is a safe bet. On the ground level, time-tested footwear with a slightly blue-collar edge, such leather boots or boat shoes, complement the classic CPO jacket. For a more formal look, you can wear a solid-colored CPO jacket as a sport coat or blazer with a pair of fitted chinos, a lightweight solid-colored button-up and leather loafers or ankle boots, with an optional scarf for added interest. Keep your pairings simple, masculine and earthy when sporting a CPO; the military roots of this garment give it a utilitarian vibe that works best with neutral tones, leather accents and classic cuts.