noun
short sword; small sword
Refers to a shorter Japanese sword, often used as a companion to a longer sword (e.g., in a daishō pair).
侍は腰に小太刀を差していた。
The samurai wore a short sword at his waist.
Compound of 小 (ko, 'small') and 太刀 (tachi, 'long sword'). The reading こだち is a rendaku form of こ + たち.