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

    e.g. ...the commonly accepted norms of democracy.
           被人们普遍接受的民主准则
    e.g. ...a social norm that says drunkenness is inappropriate behaviour.
           认为醉酒是不当行为的社会规范

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

norm的近义词

    e.g. Families of six or seven are the norm in Borough Park...
           在区公园住宅区六口或七口之家十分普遍。
    e.g. The changes will lead to more flexible leases, and leases nearer to 15 years than the present norm of 25 years.
           这些变化将带来更灵活的、接近15年的租期，而不是现行的常规为25年的租期。

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

    e.g. ...an agency which would establish European norms and co-ordinate national policies to halt pollution.
           确立各项欧洲环保标准、协调各国政策以阻遏污染的机构