A shirt jacket is a garment that combines the features of a shirt and a jacket. It is often a slightly thicker shirt, usually made from heavier materials like wool, flannel, or sturdy cotton, making it more suitable as outerwear in milder weather. The shirt jacket often has a shirt collar, front buttons, and may have pockets like a traditional jacket. It’s perfect for a layered look, as it can be worn over a t-shirt or sweater when it’s a bit chilly outside but not cold enough for a full jacket.