This is the 5314th most frequent Japanese word.
fi
The term "fi" does not have meaning as a Japanese word; it may be a misinterpretation or misspelling.
In this sentence, 'fi' is used as a term that I am planning to study.
私はフィを学ぶために新しい本を買いました。
I bought a new book to learn about 'fi'.
Here, 'fi' refers to a term or concept whose usage affects its meaning.
フィの使い方によって意味が変わります。
The meaning changes depending on the use of 'fi'.
In this context, 'fi' is mentioned as a concept the subject was unfamiliar with.