n. and adj.
Marching band, simply, is a group of people who play certain types of musical instruments - notably, brass, woodwinds, drums/percussion - and march with them.
Some marching bands are comprised of people who have written these other Urban Dictionary definitions. Some marching bands are comprised of people who are offended by these other Urban Dictionary definitions, which in either case are describing far more than simply marching band.
Marching band, as a genre, is not limited by the season of the year; school, organization or community membership; age of the individual performer; musical selections or styles; and most obviously, level of devotion, values, character, focus, as well as hype or other nonsense. Just as there are good and bad performances, there are good and bad marching bands and good and bad members and players. All of these variables are determined by the individual marching band's membership, requirements and leadership/organization (or lack).
The general reader is advised to learn about marching band from people who are excited about marching and the playing of musical instruments, and ignore input from those who need or prefer to focus on other alleged characteristics.
Marching band instrumentation became focused on the three instrument classes of brass, woodwinds and percussion due to the combination of increased portability, durability and ability to be heard both indoors and outdoors. There are other sorts of instruments - notably strings, such as violins and guitars, and larger percussive instruments, such as pianos and harps, which are welcome in indoor orchestra halls but never became popular as a part of bands due to problems with durability and portability. Woodwinds are an instrument class which are sometimes eliminated from marching bands for these reasons, and such marching bands are more properly termed brass bands
due to being comprised solely of brass and drums/percussion. Alternatively, woodwinds are often valued by other marching bands, whether due to the quality of their indoor woodwind players, their contributions to the total sound of the band in all settings, the desire to be inclusive to all members, or combination thereof. Such outdoor portability and performance utility no doubt contributed throughout history to the formation of what we know as a band, which can perform well both indoors and outdoors without a large scale change of instrumentation.
Marching band was developed by people who played instruments indoors who wished to play and perform outdoors, as well as people united by other interests and associations who chose playing band instruments as an activity. Examples of the former are musicians who play trumpet, saxophone, drums, etc.; examples of the latter include fraternal organizations and businesses (such as those who built the British brass band
movement in the 1800s, or those seeking a method to advertise their name such as the USA's Goodyear Community Band).
"Marching" can range from a group of individuals merely walking together to the most perfectly uniform and military-styled precision, in step and in time with the music. The term "marching" is sometimes misused to signify other forms of outdoor performance.
In addition to the music makers, marching bands may have auxiliary units such as drill teams, dance squads, honor guards, color guards and other sections associated with them. These other sections may or may not be considered an integral part of the marching band, again depending upon the individual marching band.
Marching bands have developed in most countries over the past two centuries as a way to provide live music to listeners, both indoors and outdoors.