compass

Compared meaning: the extent or limit something covers (noun).

比较义项：某事物所涵盖或达到的范围、限度（名词）。

• scope

  Scope marks the boundary of what a subject, task, plan or person's authority covers; common in formal or professional contexts, often paired with phrases meaning 'beyond' or 'within' that boundary, or 'narrow/widen' it.

  scope强调某个学科、任务、计划或职权所涵盖的边界，常用于正式或专业场合，人们常说某事“超出scope”或“缩小/扩大scope”。

  Discussing salary is beyond the scope of today's meeting.

  讨论薪水超出了今天会议的范围。

• range

  Range highlights the variety of different types or items within one category, and is typically used with countable things like products, options or skills, as in describing something as offering a wide selection.

  range强调同一类别内不同种类或项目的多样性，通常与产品、选项等可数事物搭配，常说“种类繁多的range”或“广泛的range”。

  The bakery offers a wide range of gluten-free breads and cakes.

  这家面包店提供种类繁多的无麸质面包和蛋糕。

• reach

  Reach refers to how far someone's or something's influence, ability or effect extends, whether a physical distance or a figurative limit, often describing what is or is not attainable for someone.

  reach指某人或某事物的影响力、能力或效力所能达到的远近，可指实际距离，也可指比喻意义上的限度，常用来描述某事对某人来说是否力所能及。

  Owning a home in that city is beyond his reach financially.

  在那个城市买房在经济上是他力所不能及的。

• compass 本词

  Compass is a formal, rather literary word for the extent or range of something, used mainly in written or academic style, especially in the fixed phrase describing what falls within that range.

  compass是较为正式、书面化的说法，指某事物的范围或限度，多用于书面或学术语体，常出现在描述某事是否落在这个范围之内的固定说法中。

  No one can master every language within the compass of a single lifetime.

  没有人能够在一生的时间范围内掌握所有语言。

Scope, range, reach, and compass all mean the extent something covers. Scope is a task's or authority's limit. Range means variety within a category, like products. Reach is how far influence extends. Compass is formal, literary. Reach's 'touch' and compass's 'direction' meanings are not compared.

这四个词在“范围、限度”这一义项上比较接近，容易混淆，但语气和用法不同：scope和range常用于日常或专业语境，reach强调影响力或效力所能达到的远近，compass语气最为正式、书面化。这里不比较reach作动词“伸手够到”的用法（如“you can reach the top shelf”），也不比较compass更常见的“指南针”义项。