1The leading role in a play, movie, or story; the main character, or the actor/actress who plays that part.
彼女は今度の映画で主役を演じることになった。
She has been cast in the leading role in the upcoming movie.
このドラマの主役は人気の若手俳優が務めている。
A popular young actor plays the lead role in this drama.
誕生日会では、主役はやはり本人だ。
At a birthday party, the person being celebrated is naturally the star of the occasion.
彼はいつも脇役ばかりで、なかなか主役になれない。
He always ends up in supporting roles and rarely gets to be the lead.