also: とうし
noun
small ornamental knife; letter opener
Refers to a small knife, often decorative, used for opening letters or similar light tasks. Compare with 小刀 (こがたな), a small utility knife.
See also: 小刀
彼は手紙を開けるために刀子を使った。
He used a small ornamental knife to open the letter.
小刀 is a small utility knife for practical cutting tasks, while 刀子 is more ornamental and often used as a letter opener.
The kanji 刀 (sword/knife) and 子 (small thing) combine to mean 'small knife'. The reading とうす is the standard on'yomi, while とうし is a less common variant.