Tertiary
叔 (shū) / 三级 (sān jí)
Explanation (EN)
In organic chemistry, tertiary refers to a carbon atom that is bonded to three other carbon atoms. Tertiary carbon atoms are generally less reactive than primary or secondary carbon atoms due to increased steric hindrance.
Explanation (ZH)
在有机化学中，叔是指与另外三个碳原子键合的碳原子。由于空间位阻增加，叔碳原子的反应性通常低于伯碳原子或仲碳原子。
About the IPA
The International Phonetic Alphabet is a standardized system of symbols used to represent the sounds of spoken language.
It helps linguists, language learners, and educators accurately describe pronunciation across languages.
Example: the word "hello" in British English is transcribed as /həˈləʊ/ in IPA.