knife in Chinese:

1. 刀

Chinese word "knife"(刀) occurs in sets:

Household Items 家居用品 Jiājū yòngpǐn
厨房，做饭 - Kitchen and cooking
Chinese radicals

2. 刀子

Chinese word "knife"(刀子) occurs in sets:

名词：单数和复数 - Noun: Singular and Plural nouns
在餐馆 - At the restaurant
Dining room vocabulary in Chinese