A flag is a piece of fabric (most often rectangular or quadrilateral) with a distinctive design and colors. It is used as a symbol, a signaling device, or for decoration. The term flag is also used to refer to the graphic design employed, and flags have evolved into a general tool for rudimentary signaling and identification, especially in environments where communication is challenging (such as the maritime environment, where semaphore is used). Many flags fall into groups of similar designs called flag families. The study of flags is known as “vexillology” from the Latin vexillum, meaning “flag” or “banner“.