Sentai

Sentai (戦隊) in Japanese language is a word for a military unit and may be literally translated as "squadron", "task force", "group" or "wing". The terms "regiment" and "flotilla", while sometimes used as translations of Sentai, are also used to refer to larger formations.

World War II
It is perhaps best known as a term used during World War II by the military of the Empire of Japan, for Imperial Japanese Army Air Force (IJAAF) and Imperial Japanese Navy Air Service (IJNAS) military aviation units equivalent to a group or wing in other air forces. However, the term had slightly different meanings in the IJAAF and the IJNAS.

An IJAAF Sentai was made up of two to four squadrons (chūtai). In the IJAAF, two or more Sentai comprised a hikōdan (air brigade). In the later stages of World War II, the IJAAF abolished chūtai and divided its sentai into hikōtai (flying units) and seibitai (maintenance units). A sentai commander (sentaichō) was generally a Lieutenant Colonel.

In the IJNAS, a sentai was a larger unit: a kōkūtai was the equivalent of an IJAAF sentai. Several sentai made up a kantai (air fleet). In the IJNAS, a Sentaichō was usually a Naval Captain.

Super Sentai
The Super Sentai Series (スーパー戦隊シリーズ) is a franchise of Japanese tokusatsu television dramas that uses the word sentai to describe a group of between 3 or more costumed superheroes (whose core team generally consists of five members) who often pilot mecha.