role

Compared meaning: someone's or something's job in an activity (noun).

比较义项：角色，职责（某人或某物在某项活动、工作或系统中所起的作用）（名词）。

• part

  Informal and typically used for someone's role in a play, story, or shared activity; often collocated with 'play' (play a part) or 'take part in'.

  较为口语化，通常指某人在戏剧、故事或共同活动中扮演的角色；常与 play（扮演）或 take part in（参加）搭配使用。

  During rehearsals, he practiced his part until he knew every line by heart.

  排练时，他反复练习自己的角色，直到记住了每一句台词。

• role 本词

  The most general, neutral word for someone's job, position, or duty in a team, organization, or situation; more formal than 'part'.

  是最通用、较中性的词，指某人在团队、组织或某种情境中的工作、职位或职责；比 part 更正式。

  As a nurse, her role is to support patients as well as treat their injuries.

  作为一名护士，她的职责不仅是治疗病人的伤情，还要给予他们支持。

• function

  Focuses on the actual purpose or way something works, and is commonly used for machines, organs, or systems, not just people.

  强调事物实际发挥的作用或运作方式，除了指人以外，也常用于机器、器官或系统，而不仅限于人。

  The main function of a thermostat is to keep the room at a steady temperature.

  恒温器的主要作用是让房间保持恒定的温度。

Part, role, and function can mean a job or duty in an activity. Part is informal, used for a role in a play. Role is the general, neutral word for a job in a team. Function is the real purpose of something, often a machine.

这三个词都可以表示“角色”或“职责”，但语气和使用范围不同：part 多用于戏剧、故事或团队活动中某人所扮演的角色，语气较随意；role 是最通用、较正式的词，常指某人在工作或团队中的职位或职责；function 强调事物或人实际发挥的作用，除了人以外也常用于机器、系统等非生命事物。这里不比较 part 表示“一部分”的意思，也不比较 function 在数学中表示“函数”的意思。