noun
sword with a round pommel
Historical term for a type of Japanese sword with a distinctive ring-shaped pommel, often associated with ancient or early medieval periods.
See also: 太刀
この古墳からは環頭大刀が出土した。
A sword with a round pommel was excavated from this ancient tomb.
太刀 is a general term for a long sword worn slung from the belt, while 環頭大刀 specifically refers to a type with a ring-shaped pommel.
環頭 (ring-shaped head/pommel) + 大刀 (long sword). The exact historical origin is uncertain, but the term describes swords with a distinctive ring pommel found in ancient Japanese archaeological sites.