This is the 7458th most frequent Japanese word.
健史
"健史" is a Japanese male given name, typically meaning "healthy" (健) and "history" or "chronicle" (史).
Here, '健史' (Takeshi) is used as a proper noun, referring to the name of a person.
健史さんは毎日ランニングをしています。
Mr. Takeshi runs daily.
Here, '健史' represents the given name of someone's son, demonstrating the use of '健史' in naming.
彼の息子の名前は健史です。
His son's name is Takeshi.
In this context, '健史' is referred to as a name, and the sentence comments on the uniqueness of the name.