Aside from tricking everyone into thinking they've made a typo, the Spere Jacket from Arc'teryx does a great job of occupying that nebulous location that exists somewhere between an overshirt and a light jacket.
What defines the turning point where a shirt becomes a jacket? Experts would tell you there's a predetermined set of features which help to define them, but we all know that's not true.
Constructed from a wind and waterproof Terratex™ outer, the simple shape is defined by the minimalist silhouette which does well to hide a stacking pocket system which will fit plenty.