The term “livery” is used in a wide variety of ways, betraying its complex history. Today, the term may be found used in reference to uniforms, official insignia meant to identify something as the belonging of a person or corporation, and in the sense of a company which offers various methods of transportation for hire.
Livery is derived from the French word livree, which means “delivered.” It originally took the form of a gift from the master of a house or manor to servants and followers, and such gifts could take a variety of forms, including land, clothing, food, ornaments, and other goods. Often, servants stored these gifts in a “livery cupboard.”
Over time, many lords began to outfit their higher ranking servants in livery, for a variety of reasons. The ability to afford fancy outfits would have been a status symbol, indicating that a lord could afford to dress his servants, especially in a household where different liveries were used at different times of the day, and for different events. Liveried servants were also easy to identify, differentiating them from the residents of the house and making it easy to know who they were loyal to when they traveled. Liveried servants also, of course, would have looked very impressive to visitors.
Not everyone was entitled to livery. It was generally reserved for higher-ranking servants who would be seen by residents of the household, and there were ranks of livery which entitled servants to specific privileges. A servant's rank could be determined by the style he wore, and various insignia on the clothing. Female servants did not wear such outfits, although some attempts were made to design livery for women at various points in history.
The use of livery for servants faded out in the early years of the 20th century, replaced with more generic uniforms. Examples of livery can be seen in paintings and the form of preserved garments in museums, illustrating the range of designs and colors which could be worn.
Followers of royalty and lords might also wear livery, in the form of a badge or insignia which identified them to others. As a general rule, a follower had to be granted the right to wear such clothies; in other words, someone couldn't just decide to wear something which identified them as a follower of a specific person, they had to demonstrate loyalty. This type of outfit often appears in works of art in the form of badges, necklaces, and so forth.