## Sigma (Σ) ### English **Meaning:** A symbol used in mathematics to denote summation. It's often used in casual speech to refer to someone or something that's absolutely necessary or central to a situation. **Example:** "The sigma of the team is the coach, who inspires and keeps everyone in line." ### Chinese ** Meaning:** 一个在数学中用来表示求和的符号。在非正式场合，它常用来指代某个角色或事物在情况中是绝对必要或核心的部分。 **例句:** "团队的 sigma 是教练，他鼓舞并保持大家的秩序。"