Busho refers to those who stood out among people engaged in military affairs, such as a military officer and a samurai. Its synonymous words are taisho and sho that is simply an abbreviation. It is mostly used in Oriental history including India.
Usage in Japanese history
In Japanese history, it is mostly used for an outstanding warrior from the late Heian period to the Azuchi-Momoyama period and the early days of the Edo period. To indicate their affiliation or era, their master's name or era may be prefixed, such as "Heike's busho" (warriors of Taira family) and "sengoku busho" (warriors in the Sengoku Period (Period of Warring States)). From which status or rank may be called sho has not been defined.
People after the mid-Edo period are rarely called busho. For example, the commanders of various end-of-Edo-period corps are called by their official titles, such as, taicho (captain), sotoku (chief), sanbo (staff officer), and shimo-sanbo (lower staff officer). Busho is not usually used to address them.
Usages other than Japanese history
In Oriental history other than Japanese, it is used for an outstanding warrior before modern ages. Moreover, a high ranking busho may be called shogun. In Western history, shogun is often used to address an outstanding warrior while busho is rarely used.