A tweed jacket is a type of men's or women's clothing that features a woolen fabric with an irregular, heathered pattern. The term "tweed" specifically refers to a particular style of weaving that produces the characteristic diagonal lines and flecks in the material. Tweed jackets are typically associated with classic British fashion and can range from casual to formal depending on the cut, color, and details such as buttons or lapels. They often have a timeless, vintage appeal and are popular choice for both business attire and weekend wear.