1. 行为准则;规范
Norms are ways of behaving that are considered normal in a particular society.

2. 通例;常规
If you say that a situation is the norm, you mean that it is usual and expected.

3. 标准;规范
A norm is an official standard or level that organizations are expected to reach.

1. a statistic describing the location of a distribution

e.g. it set the norm for American homes

Synonym: average

2. a standard or model or pattern regarded as typical

e.g. the current middle-class norm of two children per family