This is the 2333rd most frequent Chinese word.
乃
"乃" means "is," "indeed," or "thus," often indicating causation or emphasis.
In this sentence, '乃' is used as a literary and formal substitute for '是', indicating equivalence or being.
此事乃昨日发生的。
This event occurred yesterday.
Here, '乃' expresses subject-predicate relation, formal and poetic in tone, often used to emphasize important statements.
君乃知己，此生有幸。
You are a soulmate; I'm fortunate in this life.
In this example, '乃' is utilized as 'is', often seen in proverbs or expressions of general truth, providing a tone of importance and classicism.