A role, assignment, responsibility, duty, or function — the job someone performs.
会議で私は経理の役を任された。
At the meeting I was assigned the accounting role.
彼女はチームで重要な役を果たしている。
She plays an important role in the team.
子どもの教育は親の大切な役目だ。
Educating children is an important duty of parents.
このプロジェクトでは君に広報の役を頼みたい。
I want to ask you to take on the PR role for this project.
A post, position, or office — a job or official position of responsibility.
町内会の役を引き受けた。
I took on an office in the neighborhood association.
会社で新しい役に就くことになった。
I will assume a new position at the company.
その役は責任が重く、経験が必要だ。
That position carries heavy responsibility and requires experience.
A part or role in a play, film, etc.; a character someone plays (lead, supporting, etc.).
彼は映画で主役を演じた。
He played the lead role in the film.
この役は脇役だが印象的だ。
This is a supporting role, but it's memorable.
あの役を演じるには幅広い表現力が必要だ。
To play that role you need a wide range of expression.
In mahjong (and some card games), a scoring combination or 'yaku' — a specific hand or meld that yields points.
「タンヤオ」は初心者にも覚えやすい役です。
'Tanyao' is an easy yaku for beginners to remember.
その手は高い役がついているので点数が高い。
That hand has a high yaku, so the score is high.