This is the 3138th most frequent Japanese word.
刀
Sword; specifically, a Japanese blade.
The word "刀" here illustrates its functional aspect, considered as an object which is legally regulated.
刀を持ち歩くことは禁止されています。
Carrying a sword is prohibited.
In this sentence, "刀" emphasizes the historical significance and method of creation of the sword.
この刀は数百年前に鍛造されたものです。
This sword was forged hundreds of years ago.
Here, "刀" refers to a physical sword, highlighting its design and craftsmanship.