noun
two-sworded samurai; wearing two swords
Refers to a samurai who wears both a long and a short sword, the traditional mark of the warrior class in the Edo period.
江戸時代、武士は二本差しであることが身分の証だった。
In the Edo period, being two-sworded was a mark of a samurai's status.
大小 refers to the pair of long and short swords themselves, while 二本差し describes the person wearing them.
Compound of 二本 (two long, thin objects) and 差し (from 差す, to wear at one's side).