noun
chief warrant officer (Japanese Imperial Navy)
Historical rank in the Imperial Japanese Navy, roughly equivalent to a chief warrant officer. Cross-referenced with 准尉 (jun'i, warrant officer).
See also: 准尉
彼の祖父は旧日本海軍の兵曹長だった。
His grandfather was a chief warrant officer in the former Imperial Japanese Navy.
准尉 is a warrant officer, while 兵曹長 is specifically a chief warrant officer in the Imperial Japanese Navy, a higher rank.
Compound of 兵曹 (heisō, a naval non-commissioned officer rank) and 長 (chō, chief). The exact historical derivation is uncertain.