This is the 9686th most frequent Japanese word.
芯
Core; center; heart; wick.
The term '芯' here is used to refer to the inner core of the pencil, specifically the lead.
この鉛筆の芯が折れてしまった。
The lead of this pencil has broken.
In this sentence, '芯' symbolizes inner strength or fortitude, emphasizing the metaphorical concept of a person's resolute core.
彼女は芯の強い人です。
She is a person with strong inner strength.
Here, '芯' refers to the physical core or center of the apple, highlighting its literal usage.