原理 (yuán lǐ) means “principle; theory”. It is an HSK 6 Chinese word in the HSK 3.0 vocabulary.
Practice each character:
老师解释了这个科学原理。
Lǎoshī jiěshì le zhège kēxué yuánlǐ.
The teacher explained this scientific principle.
Updated: 2026-05-27