On a recent trip to Portugal, I found myself combining wide-leg pleated denim trousers, voluminous vintage silk parachute shirts from Katharine Hamnett, and Yuri & Yuri’s delicate crochet knits—all in a spectrum of khaki hues, from dull green to brownish yellow. To my surprise, they blended together effortlessly. Turns out, so did a tan.
While the prevalence of khaki—a term derived from the Persian word for “dusty”—is an exemplar of the military’s influence on

