This is the 1502nd most frequent Japanese word.
たぶん
"たぶん" means "probably" or "perhaps."
たぶん is used here to express uncertainty, suggesting a possibility.
たぶん、もう彼は家に帰ったと思います。
Perhaps, he has already gone home.
Here, たぶん is employed to anticipate a likely future event.
たぶん明日は晴れるでしょう。
Maybe tomorrow will be sunny.
In this case, たぶん conveys doubt regarding someone's knowledge.