class

Compared meaning: a class or year-level in school (noun).

比较义项：年级／班级（名词）。

• grade

  Refers to a year-level in school (a stage a student is in, e.g. fifth grade), used mainly in American English; focuses on the student's level, not the classmates.

  指学校里的一个年级（学生所处的阶段，例如五年级），主要用于美式英语；强调学生所在的年级阶段，而不是同学群体。

  My daughter is starting third grade at a new school this fall.

  我女儿这个秋天要在一所新学校上三年级。

• class 本词

  Refers to a group of students who study or are taught together, often in one room; focuses on the group of people, not the year-level, and can also mean a single lesson period.

  指一起学习或被一起授课的一群学生，通常在同一间教室里；强调的是这群人本身，而不是年级阶段，也可以指一节课。

  Our class voted on where to go for the school trip.

  我们班投票决定了校外教学要去哪里。

Grade and class both describe a school group organized by age or level. Grade focuses on a student's year-level, used mainly in American English. Class focuses on the group of students who study together, and can also mean one lesson.

grade 和 class 在“学校中按年龄或程度划分的教学单位”这个意思上很接近，学习者容易混用，但 grade 强调的是学生所处的年级／年龄阶段，class 强调的是一起上课的那群学生（班级群体）。grade 还有“分数、成绩等级”的意思，class 还有“阶级；课；种类”等意思，这里都不比较。

Compared meaning: a group of things with shared features (noun).

比较义项：具有共同特征的种类、类别（名词）。

• category

  Category highlights a group defined by shared characteristics within a classification system, commonly used for sorting items, genres, or entries, as in a product or complaint category.

  category强调在分类体系中按共同特征归类的群体，常用于对物品、体裁或条目进行分类，例如产品类别或投诉类别。

  The judges placed her painting in the wrong category.

  评委把她的画归错了类别。

• class 本词

  Class often denotes a type or grade within a technical, scientific, or hierarchical classification, such as a class of drugs or vehicles, and can carry a sense of rank or quality.

  class常指技术性、科学性或带等级意味的分类中的一种类型或等级，例如药物类别或车辆类别，有时还带有等级或品质的含义。

  Insulin belongs to a class of drugs called hormones.

  胰岛素属于一类被称为激素的药物。

Category and class both mean a group of things with shared features. Category stresses fitting something into a classification system, often for sorting items. Class is more common in technical or scientific classification, like a class of drugs, and can carry a sense of rank.

这两个词表示“种类”时意思相近，但category强调按共同特征归入某个分类体系，常用于对物品、体裁或条目进行分类；class则更常见于技术性、科学性或带等级意味的分类，如药物类别或车辆类别。这里不比较class的“班级”（学生群体）或“社会阶层”等含义。

Compared meaning: a social class or level in society (noun).

比较义项：阶层（名词）。

• class 本词

  The everyday, common word for a social or economic group, as in 'working class' or 'middle class'; used in both casual speech and formal writing.

  这是表示社会或经济群体的日常常用词，如working class（工人阶级）、middle class（中产阶级）；口语和书面语中都很常见。

  She grew up in a working-class family in a small town.

  她在一个小镇的工人阶级家庭中长大。

• stratum

  A formal, academic word, often used as the plural 'strata', borrowed from geology; it stresses a layered social hierarchy and appears mainly in scholarly or sociological writing, rarely in casual speech.

  这是一个正式、学术化的词，常以复数strata出现，源自地质学；它强调社会等级的分层结构，多见于学术或社会学类的写作，口语中很少使用。

  Economists identify several distinct social strata based on wealth and occupation.

  经济学家根据财富和职业划分出几个不同的社会阶层。

Class and stratum can both mean a social level in society. Class is the everyday word, used in speech and writing, as in working class. Stratum is a formal, academic word, often used in its plural form strata, common in scholarly writing about society.

class 和 stratum 都可以表示社会中的“阶层”，但 class 是日常用语，使用范围更广，口语和书面语都常见；stratum 则更正式、学术化，常以复数 strata 出现，强调社会分层，多见于社会学类的论述。这里不比较 class 的“类别”“班级”等义，也不比较 stratum 的“岩层”义。