Aikidogi
Aikidogi (合気道着 or 合気道衣) is the formal Japanese name for the uniform used for aikido training. Most practitioners simply call it a dogi (a more generic term, covering all kinds of martial arts) or gi (which is an improper abbreviation as it doesn't make sense in Japanese ). There are few if any rules regarding the aikido uniform other than local or organizational guidelines, though for reasons of tradition most aikidoka wear an aikidogi that is made from bleached (or occasionally unbleached) cotton or sometimes cotton-polyester blends.
Practically aikido training sits somewhere between judo and karate in the nature of its practice and therefore it is very common to find both lightweight karategi and heavier judogi being used by aikidoka depending on preference. Both are more durable than typical Western clothing. A judogi is typically thick enough to support the weight of its wearer. Some variation is found even within an individual organization or dojo depending on the instructor(s).
In addition to judogi and karategi used for aikido practice there are also a small number of companies which manufacture keikogi specifically for aikido training. These tend to differ from other styles of keikogi in subtle ways reflecting some of the unique aspects of aikido training, such as shorter sleeves reaching to just below the elbow. Unlike many other martial arts aikido continues to emphasize defences from a seated position and therefore aikidogi often have heavily reinforced zubon or pants (especially kneepatches) and also tend to have slightly longer skirts around the waist of the uwagi or jacket to allow the aikidoka to tuck their uwagi into their hakama without any trouble. Additionally aikido uwagi tend to have slightly shorter sleeves to facilitate training from wrist grabs which is very common, especially at lower levels. Some aikidogi are derived from judogi and have a heavyweight tightly woven terrycloth style uwagi, while others are made from a heavy canvas karategi style material strong enough for regular grappling and throwing found in aikido training.