1An adverb expressing the speaker's belief that something is likely, though not certain — 'probably', 'most likely', 'maybe'. Very common in everyday conversation.
多分明日は晴れると思うよ。
I think it'll probably be sunny tomorrow.
「彼、パーティーに来るかな？」「多分ね。」
"Is he going to come to the party?" "Probably."
連絡がないから、たぶん忘れているんだろう。
He hasn't been in touch, so he's probably forgotten.
たぶん駅の近くにコンビニがあったはずだ。
There was probably a convenience store near the station.
2(Somewhat dated/formal) a large amount or degree; chiefly used in the forms 多分の... or 多分に. Rarely used in everyday speech, where 多くの is normal.
この事業には多分の危険が伴う。
This venture involves a considerable amount of risk.
彼の成功には多分に運の要素があった。
His success owed much to an element of luck.