 The term "flag" is also used to refer to the graphic design employed, and flags have evolved into a general tool for rudimentary signalling and identification, especially in environments where communication is challenging (such as the maritime environment, where semaphore is used).The study of flags is known as "vexillology" from the Latin "vexillum", meaning "flag" or "banner".National flags are patriotic symbols with widely varied interpretations that often include strong military associations because of their original and ongoing use for that purpose.